Halacha

הלכה א
מָקוֹם שֶׁלֹּא הֻקַּף לְדירָה אֶלָּא שֶׁיִּהְיֶה תַּשְׁמִישׁוֹ לַאֲוִיר כְּגוֹן גַּנּוֹת וּפַרְדֵּסִים וּכְגוֹן הַמַּקִּיף מָקוֹם מִן הָאָרֶץ לְשָׁמְרוֹ וְכַיּוֹצֵא בָּהֶן. אִם יֵשׁ בְּגֹבַהּ הַמְּחִצּוֹת עֲשָׂרָה טְפָחִים אוֹ יֶתֶר הֲרֵי הוּא כִּרְשׁוּת הַיָּחִיד לְחַיֵּב הַמּוֹצִיא וְהַזּוֹרֵק וְהַמּוֹשִׁיט מִמֶּנּוּ לִרְשׁוּת הָרַבִּים אוֹ מֵרְשׁוּת הָרַבִּים לְתוֹכוֹ. וְאֵין מְטַלְטְלִין בְּכֻלּוֹ אֶלָּא אִם כֵּן יֵשׁ בּוֹ בֵּית סָאתַיִם אוֹ פָּחוֹת. אֲבָל אִם הָיָה בּוֹ יֶתֶר עַל בֵּית סָאתַיִם אָסוּר לְטַלְטֵל בּוֹ אֶלָּא בְּאַרְבַּע אַמּוֹת כְּכַרְמְלִית:
כסף משנה
1.
[The following rules pertain to] a place that is enclosed for purposes other than habitation, and is used as an open space - e.g., gardens and orchards, an open area that is enclosed to protect it, or the like: If the walls surrounding it are ten handbreadths or more high, it is considered to be a private domain with regard to a person's being liable for transferring, throwing, or passing an object from it to the public domain, or from the public domain to it.1The majority of this chapter is devoted to an explanation of the laws pertaining to a karpef, a large area that is enclosed by four walls, but these walls were not constructed for the purpose of habitation.
Since this area is enclosed by four walls, it is considered a private domain according to Torah law. Therefore, one is liable for transferring articles to and from it. Nevertheless, as the Rambam continues, the Rabbis imposed certain restrictions on carrying within this space for the reasons mentioned below. We are, however, allowed to carry within an area enclosed for the purpose of habitation regardless of how large it is (Rambam's Commentary on the Mishnah, Eruvin 2:5).

We are not allowed to carry within it, unless its area is equivalent to that necessary to sow two seah [of grain]2The size of this space is defined in Halachah 3. or less. If its area is larger than the space necessary to sow two seah, we may not carry more than four cubits within it, as in a carmelit.3Since this is a large space in which there are no inhabitants, it appears to resemble a public domain or a carmelit. Accordingly, the Sages placed certain restrictions on carrying within it, lest one err and carry in the public domain as well (Shulchan Aruch HaRav 358:1).

הלכה ב
וְכֵן עַמּוּד שֶׁגָּבוֹהַּ עֲשָׂרָה טְפָחִים וְרָחָב עַד בֵּית סָאתַיִם מְטַלְטְלִין עַל כֻּלּוֹ. הָיָה רָחָב עַל בֵּית סָאתַיִם אֵין מְטַלְטְלִין בּוֹ אֶלָּא בְּאַרְבַּע אַמּוֹת. סֶלַע שֶׁבַּיָּם הָיָה גָּבוֹהַּ פָּחוֹת מֵעֲשָׂרָה מְטַלְטְלִין מִתּוֹכוֹ לַיָּם וּמִן הַיָּם לְתוֹכוֹ שֶׁהַכּל כַּרְמְלִית. הָיָה גָּבוֹהַּ עֲשָׂרָה אִם הָיָה רָחְבּוֹ מֵאַרְבָּעָה טְפָחִים עַד בֵּית סָאתַיִם הוֹאִיל וּמֻתָּר לְטַלְטֵל בְּכֻלּוֹ אֵין מְטַלְטְלִין לֹא מִתּוֹכוֹ לַיָּם וְלֹא מִן הַיָּם לְתוֹכוֹ. הָיָה יֶתֶר מִבֵּית סָאתַיִם אַף עַל פִּי שֶׁהוּא רְשׁוּת הַיָּחִיד הוֹאִיל וְאָסוּר לְטַלְטֵל בּוֹ אֶלָּא בְּאַרְבַּע אַמּוֹת כְּכַרְמְלִית הֲרֵי זֶה מֻתָּר לְטַלְטֵל מִתּוֹכוֹ לַיָּם וּמִן הַיָּם לְתוֹכוֹ שֶׁזֶּה דָּבָר שֶׁאֵינוֹ מָצוּי הוּא וְלֹא גָּזְרוּ בּוֹ:
כסף משנה
2.
Similarly, if a surface is elevated more than ten handbreadths high4A surface four handbreadths by four handbreadths that is elevated ten handbreadths above the ground is considered to be a private domain. and whose area is equivalent to the space necessary to sow two seah or less, we may carry on the entire surface. If its area exceeds the space necessary to sow two seah, we may carry only within a space of four cubits upon it.5I.e., although it is a private domain according to Torah law, our Sages forbade carrying upon it for the reasons explained in the previous halachah.
When a rock in the sea is less than ten handbreadths high, we may carry from it to the sea, and from the sea to it, for the entire area is a carmelit.6Although one is allowed to carry from one carmelit to another, one may not carry more than a total of four cubits. If [the rock] is ten handbreadths high, [different rules apply]. If the size of its area is between7If it is less than four handbreadths by four handbreadths, it is a makom patur, and there is no difficulty in carrying from it to the sea or from the sea to it.four handbreadths [by four handbreadths]8A rock that is this high above the sea and this size is considered to be a private domain. and the space necessary to sow two seah, [our Sages forbade] carrying from [the rock] to the sea or from the sea to the rock. [This restriction is a safeguard, instituted,] because we are permitted to carry on the entire [rock].
If its area exceeds the space necessary to sow two seah, although it is a private domain and yet it is forbidden to carry more than four cubits upon it as in a carmelit, it is permitted to carry from it to the sea and from the sea to it. This is an atypical situation. Hence, the Sages did not [include] it [in their] decree.9Although our Sages generally forbade transferring an article from a private domain to a carmelit, since this is a very unusual circumstance they did not include it in their decree.

הלכה ג
כַּמָּה הִיא בֵּית סְאָה חֲמִשִּׁים אַמָּה עַל חֲמִשִּׁים אַמָּה. נִמְצָא בֵּית סָאתַיִם מָקוֹם שֶׁיֵּשׁ בְּתִשְׁבָּרְתוֹ חֲמֵשֶׁת אֲלָפִים אַמָּה. וְכָל מָקוֹם שֶׁיֵּשׁ בּוֹ כַּמִּדָּה הַזֹּאת בֵּין שֶׁהָיָה מְרֻבָּע שֶׁהוּא שִׁבְעִים אַמָּה וְשִׁירַיִם עַל שִׁבְעִים אַמָּה וְשִׁירַיִם בֵּין שֶׁהָיָה עָגל בֵּין שְׁאָר הַצּוּרוֹת הֲרֵי זֶה נִקְרָא בֵּית סָאתַיִם:
כסף משנה
3.
How large is an area in which a seah [of grain can be sown]? Fifty cubits by fifty cubits. Thus, the area in which two seah [of grain can be sown] is 5000 square cubits.10Eruvin 23b identifies the area in which two seah of grain can be sown with the courtyard of the Sanctuary in the desert, which was 100 cubits by 50 cubits.
The Shulchan Aruch HaRav explains the significance of this concept. All of the prohibitions against labor on the Sabbath are derived from the Sanctuary. The courtyard of the Sanctuary was a large area which was enclosed for purposes other than habitation. Nevertheless, it was permitted to carry within it. Therefore, when the Sages prohibited carrying in large areas that were enclosed for purposes other than habitation, they used the size of the courtyard of the Sanctuary as the lower limit.

This measure11Here we see a contrast to the measures of four handbreadths by four handbreadths or four cubits by four cubits, where the intent is a square or a larger area in which such a square could be inscribed. applies whether the area is a square of 70 cubits and a fraction by 70 cubits and a fraction,12In his Commentary on the Mishnah (Eruvin 2:5), the Rambam states that the square is approximately 70 cubits and five sevenths of a cubit by 70 cubits and five sevenths of a cubit, but that there is no perfect square root for the number 5000.or it is a circle, or it is of another shape.13This is obvious from the connection to the courtyard of the Sanctuary, which, as mentioned, was a rectangle and not a square. [If its area equals the sum mentioned,] it is considered as "the area in which two seah [of grain can be sown]."

הלכה ד
מָקוֹם שֶׁלֹּא הֻקַּף לְדִירָה שֶׁיֵּשׁ בּוֹ בֵּית סָאתַיִם אִם הָיָה אָרְכּוֹ פִּי שְׁנַיִם כְּרָחְבּוֹ כְּדֵי שֶׁיִּהְיֶה מֵאָה עַל חֲמִשִּׁים כַּחֲצַר הַמִּשְׁכָּן מֻתָּר לְטַלְטֵל בְּכֻלּוֹ. אֲבָל אִם הָיָה אָרְכּוֹ יֶתֶר עַל שְׁנַיִם כְּרָחְבּוֹ אֲפִלּוּ אַמָּה אֵין מְטַלְטְלִין בּוֹ אֶלָּא בְּאַרְבַּע אַמּוֹת. שֶׁלֹּא עָשׂוּ בֵּית סָאתַיִם שֶׁתַּשְׁמִישׁוֹ לַאֲוִיר כִּשְׁאָר הַחֲצֵרוֹת אֶלָּא מֵחֲצַר הַמִּשְׁכָּן:
כסף משנה
4.
[The following rules apply when] an area that is enclosed for purposes other than habitation and is large enough for two seah [of grain to be sown within is rectangular in shape]: If its length is twice its width - for example, it is 100 by 50, as was the courtyard of the Sanctuary - carrying is permitted within it.
If, however, [it is more elongated] and its length exceeds twice its width by even one handbreadth,14Note the Rambam's explanation of the difference in opinion between Rabbi Yosse and Rabbi Eliezer, in his Commentary on the Mishnah (Eruvin 2:5). On the basis of this explanation, it would appear that his conception of the Mishnah is closer to that of Tosafot, Eruvin 23b than to that of Rashi (loc. cit.). we are permitted to carry only four cubits within it.15As in a carmelit. [This restriction is imposed because the permission to carry as one may carry] in other courtyards [within] an open space large enough for two seah [of grain to be sown within], is derived from the courtyard of the Sanctuary.16Hence, when such an open area does not resemble the courtyard of the Sanctuary, the leniency does not apply.

הלכה ה
מָקוֹם שֶׁהֻקַּף שֶׁלֹּא לְשֵׁם דִּירָה אִם פָּרַץ בּוֹ פִּרְצָה יֶתֶר עַל עֶשֶׂר אַמּוֹת בְּגֹבַהּ עֲשָׂרָה טְפָחִים וְגָדַר בָּהּ לְשֵׁם דִּירָה עַד עֲשָׂרָה מֻתָּר לְטַלְטֵל בְּכֻלָּהּ. וַאֲפִלּוּ פָּרַץ אַמָּה וּגְדָרָהּ לְשֵׁם דִּירָה וּפָרַץ אַמָּה וּגְדָרָהּ לְשֵׁם דִּירָה עַד שֶׁהִשְׁלִימָהּ לְיֶתֶר מֵעֶשֶׂר מֻתָּר לְטַלְטֵל בְּכֻלָּהּ אַף עַל פִּי שֶׁיֵּשׁ בּוֹ כַּמָּה מִילִין:
כסף משנה
5.
[The status of] a place that was originally enclosed for purposes other than habitation [may be changed in the following manner]. A person tears down [a portion of the wall, creating] an open space that is more than ten cubits long and ten handbreadths high17Once this extent of a wall has been broken down, it is considered as if the entire wall is no longer of significance as indicated in Halachah 16. and then re-encloses that space for the purpose of habitation.18When one re-encloses the wall, it is considered as if the entire enclosure has been made for the purpose of habitation. Therefore, the area is considered to be an ordinary private domain, and one is allowed to carry within without restriction.
The Maggid Mishneh questions the Rambam's statements on the basis of those of Rashi, Eruvin 24a, which state that the intent to use the enclosure for habitation is not sufficient. There must be a house that opens up to the enclosure.
The Merkevet HaMishneh states that, according to the Rambam, "habitation" does not necessarily mean "human habitation." Therefore, the intent could be to use the enclosure as a corral for animals or the like. Rav Kapach cites the Rambam's Commentary on the Mishnah (Eruvin 2:5), from which it appears that as long as there is a storage vat in the enclosure, it is considered as "enclosed for the purpose of habitation," although it does not contain a house or lead to a house.
Thus according to the Rambam, "everything depends on the person's intention." If he encloses the area for the sake of habitation, he is allowed to carry freely within it. Why is this leniency granted? Because the prohibition against carrying within such an area is Rabbinic in origin, and the Sages enforced this stringency only when a person's intent was not for the sake of habitation, for then the enclosure resembles a public domain. The Shulchan Aruch (Orach Chayim 358:2), however, follows Rashi's view, that a house is required within the enclosure or the enclosure must lead to a home.
[After this has been done,] one may carry within the entire enclosure.
Moreover, even if one [did not complete the entire process at once, but rather] tore down a single cubit and re-enclosed that space for the purpose of habitation, tore down another single cubit and re-enclosed that space for the purpose of habitation19Since the entire enclosure was never opened up for ten cubits at one time, one might assume that the original enclosure was never nullified. Nevertheless, since ultimately a span of ten cubits was constructed, the enclosure is considered as פנים חדשות, "a new entity" (Shulchan Aruch HaRav 358:8). Note a parallel ruling in Hilchot Kellim 6:2. - [when one continues this process until] one re-encloses a space greater than ten cubits one may carry within the entire enclosure, even though it is several millim20A mil is approximately a kilometer in contemporary measure. in size.

הלכה ו
מָקוֹם יָתֵר מִבֵּית סָאתַיִם שֶׁהֻקַּף לְדִירָה אִם נִזְרַע רֻבּוֹ הֲרֵי הוּא כְּגִנָּה וְאָסוּר לְטַלְטֵל בְּכֻלּוֹ. נִזְרַע מִעוּטוֹ אִם נִזְרַע מִמֶּנּוּ בֵּית סָאתַיִם מֻתָּר לְטַלְטֵל בְּכֻלּוֹ. וְאִם הָיָה הַמָּקוֹם הַזָּרוּעַ יֶתֶר מִבֵּית סָאתַיִם אָסוּר לְטַלְטֵל בְּכֻלּוֹ. נָטַע רֻבּוֹ הֲרֵי הוּא כְּחָצֵר וּמֻתָּר לְטַלְטֵל בְּכֻלּוֹ. נִתְמַלֵּא מַיִם אֲפִלּוּ הָיוּ עֲמֻקִּים הַרְבֵּה אִם הָיוּ רְאוּיִין לְתַשְׁמִישׁ הֲרֵי הֵן כִּנְטָעִים וּמֻתָּר לְטַלְטֵל בְּכֻלּוֹ. וְאִם אֵינָן רְאוּיִין לְתַשְׁמִישׁ אֵין מְטַלְטְלִין בּוֹ אֶלָּא בְּאַרְבַּע אַמּוֹת:
כסף משנה
6.
When [produce] is sown in the majority of an area that is larger than the space [necessary to sow] two seah [of grain] that was enclosed for the sake of habitation, the area is considered to be a garden,21Although the area was enclosed for the purpose of habitation originally, since it is large and the person sowed produce within the majority of its space, it is clear that he considers it to be a commercial field or garden. It is not common for people to dwell in such a place (Rashi, Eruvin 23b). and it is forbidden to carry within it in its totality.22I.e., one may carry only within a square of four cubits even in the portion of the enclosure where the produce was not sown, because there is no barrier enclosing the area on the side that faces the portion where the produce has been sown (Maggid Mishneh). Alternatively, the portion in which the produce was not sown is considered to be a secondary part of the entire field in which it is forbidden to carry (Rashi, Eruvin 24a).
[The following rules apply when produce] is sown merely within a minor portion [of the enclosure]: If the portion [where the produce] was sown is equal23Obviously, if produce was sown in a smaller portion of the enclosure, the same leniency applies. The portion of a field necessary to sow two seah of grain is the upper limit. to the space [necessary to sow] two seah [of grain], one may carry within the entire [enclosure].24In such an instance, the portion of the enclosure in which produce was sown is considered like a private garden a person has in his yard.
It must be noted that in this instance, the Shulchan Aruch (Orach Chayim 358:10, following the opinion of Rabbenu Asher) is more stringent than the Rambam and forbids carrying an article from the garden to the house.
If the portion [where the produce] was sown is larger than the space [necessary to sow] two seah [of grain],25Since the produce was planted in such a large area, it is considered like a commercial garden or field.one may not carry within the entire [enclosure].26In this instance, the commentaries quote the opinion of the Maggid Mishneh mentioned above: that the portion of the enclosure facing the side where the produce has been sown is not considered to be enclosed.
The Turei Zahav 358:6 is more lenient and explains that since according to the Torah, one could carry within the entire enclosure, even according to Rabbinic law one should be allowed to carry within the portion where produce was not sown. His opinion is not, however, accepted by the later authorities.

When trees are planted in the majority [of the enclosure],27The Mishnah Berurah 358:63 states that this ruling applies even when one planted trees throughout the entire enclosure. it is considered to be a courtyard, and one may carry within the entire [enclosure].28It is a common practice to plant trees in one's yard for shade. Hence, planting them is not considered to be a sign that one no longer considers the enclosure to be intended for the purpose of habitation.
Should [the enclosure] become filled with water,29The Rashba states that this applies when the water is ten handbreadths or more deep. If it is shallower than that, there are no restrictions on carrying within the enclosure. Although Sefer HaBatim differs with this interpretation, the Rashba's ruling is accepted by the Shulchan Aruch (Orach Chayim 358:11). [the following rules apply]: If [the water] is fit to be used [by humans],30Rashi (Eruvin, loc. cit.) states that the water must be fit to drink. The Rashba and other Sephardic authorities state that it is sufficient that the water be fit for laundry and the like. This appears to be the Rambam's view. Although the Shulchan Aruch (loc. cit.) quotes Rashi's view, Sha'ar HaTziyun 358:81 states that one may rely on the Rashba's ruling. [the water] is considered to be like trees,31For, indeed, it is an advantage to have a source of water near one's home. Hence, the water does not nullify the enclosure (Rashi, loc. cit.). and it is permitted to carry within the entire enclosure. If [the water] is not fit to be used [by humans], we may carry only [within a square of] four cubits in [the enclosure].32From the gloss of the Magen Avraham 358:15, it appears that if the area in which the water is collected is set off from the enclosure as a whole because its height descends abruptly, we may carry within the remainder of the enclosure.

הלכה ז
מָקוֹם שֶׁהֻקַּף שֶׁלֹּא לְשֵׁם דִּירָה שֶׁיֵּשׁ בּוֹ בֵּית שָׁלֹשׁ סְאִין וְקֵרוּ בּוֹ בֵּית סְאָה קֵרוּיוֹ מַתִּירוֹ שֶׁפִּי תִּקְרָה יוֹרֵד וְסוֹתֵם. נִפְרַץ בִּמְלוֹאוֹ לֶחָצֵר וְנִפְרְצָה חָצֵר כְּנֶגְדּוֹ. חָצֵר מֻתֶּרֶת כְּשֶׁהָיְתָה וְהַקַּרְפַּף אָסוּר כְּשֶׁהָיָה. שֶׁאֵין אֲוִיר הֶחָצֵר מַתִּירוֹ:
כסף משנה
7.
[The following rule applies when a roof is constructed33The Maggid Mishneh explains that according to the Rambam's interpretation of Eruvin 25a, this refers to a roof that is open on all sides, which the watchmen in a garden construct for shade. The Rashba interprets that passage as referring to a roof with two proper walls that are joined at one corner. Rabbenu Chanan'el's interpretation of that passage also indicates that the sides of the covered area are entirely open.over a portion of] an area large enough for three seah [of grain to be sown within] which originally had been enclosed for purposes other than habitation: If the roof34Note the Kessef Mishneh and the Shulchan Aruch (Orach Chayim 358:12), where Rabbi Yosef Karo states that this principle applies even when the roof is sloped. Generally, the principle, "The edge of the roof is considered to descend and close off," does not apply with regard to a sloped roof. Nevertheless, since according to the Torah itself, it is permitted to carry within this enclosure, leniency is allowed. (Compare also to Chapter 17, Halachah 35.)
It must be emphasized that according to the Maggid Mishneh's understanding of the Rambam's rulings (see note 33), this entire matter is extraneous.
covers [a portion of this area] large enough for a seah [of grain to be sown], we are permitted [to carry throughout the entire enclosure] because of the roof. [The rationale is:] The edge of the roof is considered to descend and close off [the covered portion from the enclosure as a whole].35Thus, the remainder of the enclosure is not larger than the space necessary to sow two seah of grain. Hence, there are no restrictions against carrying within it.
[The following rule applies when the wall surrounding an area that was enclosed for purposes other than habitation] was torn down,36This represents the Rambam's interpretation of a passage in Eruvin 25b. Although Rabbenu Chanan'el and Rav Zerachiah HaLevi interpret the passage in this manner, the Ra'avad, Rashi, the Rashba and others follow a slightly different version of the text, and therefore interpret the passage differently. Their interpretation is quoted in the Shulchan Aruch (Orach Chayim 358:13). opening the enclosure up to an adjoining courtyard, and [a portion of the wall of the courtyard] opposite [the enclosure] was also torn down:
37According to the Maggid Mishneh (and seemingly, also according to Rabbenu Chanan'el), both openings are no more than ten cubits wide. Otherwise, it would be forbidden to carry within the courtyard. [We are] permitted [to carry] within the courtyard as [we] previously [were], and [we are] forbidden [to carry] within the enclosure as [we] previously [were].38The Maggid Mishneh and others explain that the Rambam is referring to a T-shaped area in which the enclosure opens up to the courtyard, which extends on either side. The enclosure is not considered part of the courtyard, nor is the courtyard considered part of the enclosure, and the laws that originally applied to both areas continue to apply.
According to the Maggid Mishneh, this clause is not a continuation of the first clause of this halachah, but rather a separate concept in its own right. Rav Kapach, however, notes that both the Talmud (Eruvin, loc. cit.) and the Rambam link this and the previous clause together. On this basis, he follows the interpretation of Rabbenu Chanan'el, which states that the unroofed area of the enclosure was originally not larger than the space for two seah of grain to be sown within it. Therefore, we were permitted to carry within it. When, however, the wall connecting it to the courtyard was torn down, the open space was increased and became larger than the space for two seah of grain to be sown within it. Hence, it became forbidden to carry within it.
[The rationale is:] The open space of the courtyard does not cause [carrying] to be permitted [within the enclosure].39I.e., we do not say that the enclosure becomes considered as an extension of the courtyard.

הלכה ח
הָיָה יֶתֶר מִבֵּית סָאתַיִם וּבָא לְמַעֲטוֹ בָּאִילָנוֹת אֵינוֹ מִעוּט. בָּנָה בּוֹ עַמּוּד בְּצַד הַכֹּתֶל גָּבוֹהַּ עֲשָׂרָה וְרָחָב שְׁלֹשָׁה אוֹ יֶתֶר הֲרֵי זֶה מִעוּט. פָּחוֹת מִשְּׁלֹשָׁה אֵינוֹ מִעוּט שֶׁכָּל פָּחוֹת מִשְּׁלֹשָׁה כְּלָבוּד דָּמִי. וְכֵן אִם הִרְחִיק מִן הַכֹּתֶל שְׁלֹשָׁה וְעָשָׂה מְחִצָּה הֲרֵי זֶה מִעוּט. פָּחוֹת מִשְּׁלֹשָׁה לֹא עָשָׂה כְּלוּם:
כסף משנה
8.
When [the area of an enclosure] is greater than the space necessary [to sow] two seah [of grain], and one attempts to reduce its size40So that one will be able to carry within it. by planting trees, its [size is not considered to have been] reduced.41Since it is common to plant trees in such enclosures, even when the trees are ten handbreadths high and four handbreadths by four handbreadths in area (at which point they are considered to be a separate domain in certain contexts), they do not reduce the size of the enclosure (Maggid Mishneh in the name of the Rashba).
If one builds a pillar ten [handbreadths] high and three or more [handbreadths] wide at the side of the wall,42Rashi interprets Eruvin 25a, the source for this halachah, as referring to a pillar of this size, whether it is in the middle of the enclosure or next to the wall. Rashi's interpretation is followed by the Shulchan Aruch (Orach Chayim 358:5). [the size of the enclosure is considered to have been] reduced.43Thus, if the area of the enclosure minus the area of the pillar is less than 5000 square cubits, one is allowed to carry within it. If, however, [the pillar] is less than three [handbreadths] wide, [the size of the enclosure is not considered to have been] reduced, for an entity that is within three handbreadths of an existing entity is considered to be an extension of the latter entity.44Based on the principle of l'vud, the pillar is not considered to be an independent entity, but rather an extension of the wall. Therefore, although in practice, the open space within the enclosure has been reduced in size, this reduction is not considered as halachically significant.
Similarly, a person who erects a partition that is more than three [handbreadths] removed from the wall [is considered to have] reduced [the size of the enclosure].45I.e., the size of the enclosure is calculated from the new partitions. If it is less than 5000 square cubits, one may carry within. It must be noted that, with regard to this clause as well, Rashi interprets the Talmudic passage differently, explaining that the new partition is erected to enclose the area for the purpose of habitation. His interpretation is accepted by the Shulchan Aruch (loc. cit.:6). If [the partition] is less than three [handbreadths from the wall], it is of no consequence.46Because of the principle of l'vud.
The Maggid Mishneh questions this ruling on the basis of the first clause of the following halachah, which states, "If one applies cement to the wall, one reduces [the size of the enclosure]." Since the cement reduces the size of the enclosure, even though it actually becomes part of the wall, one could surely assume that a new partition would reduce the size of the wall although it is considered part of the wall because of the principle of l'vud.
The Maggid Mishneh explains that since the partition is halachically insignificant, it cannot take the place of the previous wall. Hence, it is not considered to reduce the size of the enclosure. In contrast, the cement adds on to the size of the previous wall, and the space it takes up is subtracted from the open space of the enclosure.

הלכה ט
טָח אֶת הַכֹּתֶל בְּטִיט אַף עַל פִּי שֶׁאֵינוֹ יָכוֹל לַעֲמֹד בִּפְנֵי עַצְמוֹ הֲרֵי זֶה מִעוּט. הִרְחִיק מִן הַתֵּל שְׁלֹשָׁה וְעָשָׂה מְחִצָּה הוֹעִיל. עָשָׂה מְחִצָּה עַל שְׂפַת הַתֵּל אֵינוֹ מוֹעִיל שֶׁהָעוֹשֶׂה מְחִצָּה עַל גַּבֵּי מְחִצָּה אֵינוֹ מוֹעִיל. נִבְלְעָה מְחִצָּה הַתַּחְתּוֹנָה וַהֲרֵי הָעֶלְיוֹנָה קַיֶּמֶת. הוֹאִיל וְנַעֲשֵׂית הָעֶלְיוֹנָה לְשֵׁם דִּירָה וַהֲרֵי אֵין שָׁם נִרְאֶה אֶלָּא הִיא הֲרֵי זֶה הוֹעִיל וּמֻתָּר לְטַלְטֵל בְּכֻלָּהּ:
כסף משנה
9.
If one applies cement to the wall, one reduces [the size of the enclosure],47I.e., if the entire space taken up by the cement that is added to the wall is sufficient to reduce the size of the enclosure to less than 5000 square cubits, one may carry within the enclosure. although [the cement] is not substantial enough to stand as a separate entity.48In this instance as well, the Ra'avad differs with the Rambam. Based on his interpretation of Eruvin 25a, the cement is counted only when it is substantial enough to stand on it is own if the original wall was removed. Although the Shulchan Aruch (Orach Chayim 358:7) follows the Ra'avad's view, the Mishnah Berurah 358:55 states that the Rambam's opinion may be relied upon in time of need.
[The following rule applies when an area which is larger than the space required to sow two seah of grain is located on a mound:] If one builds a wall [with the intent of enclosing the area for habitation] at the edge of the mound, it is not of consequence,49We are speaking about a mound ten handbreadths high which is considered as set apart as a separate domain. Since the area is being surrounded by a partition that is constructed for the purpose of dwelling, one might think that it would be permissible to carry within the enclosure. Nevertheless, this is forbidden for the reason stated by the Rambam. for a partition that is built on top of another partition is of no consequence.50Since the mound, the original dividing point for the enclosure, is still standing, the new walls built are not considered significant.
[The following rule applies when] a wall [that was constructed for the purpose of habitation was built] on top of a wall [that was not constructed for the purpose of habitation,]51As mentioned in the previous clause, as long as the original wall is visible, the new wall is of no consequence. the lower wall sunk within the ground,52And less than ten handbreadths of the original wall extends above the ground (Mishneh Berurah 358:57). and the upper wall remained: Since the upper wall was constructed for the purpose of dwelling, and it is the only [wall] visible at present, it is [now] considered of consequence and one may carry within the entire [enclosure].

הלכה י
רְחָבָה שֶׁאֲחוֹרֵי בָּתִּים יְתֵרָה עַל בֵּית סָאתַיִם אֵין מְטַלְטְלִין בָּהּ אֶלָּא בְּאַרְבַּע. וַאֲפִלּוּ הָיָה פֶּתַח הַבַּיִת פָּתוּחַ לְתוֹכָהּ. וְאִם פָּתַח הַפֶּתַח לְשָׁם וְאַחַר כָּךְ הִקִּיפָה הֲרֵי זוֹ כְּמֻקֶּפֶת לְדִירָה וּמֻתָּר לְטַלְטֵל בְּכֻלָּהּ:
כסף משנה
10.
We may carry only within [a square of] four cubits in a yard53Our translation is based on the Mishnah Berurah 359:1, which states that in Talmudic times there would be yards both in front and behind the homes. A yard in front of a home was referred to as a חצר. These were frequently used by the people of that era and mentioned often in the Talmud. A yard behind a home was referred to as a רחבה, a term used comparatively rarely in the Talmud. These yards were used infrequently by people of that era. that is located behind [a group of] houses larger than the space necessary [to sow] two seah [of grain], even when there is an opening from [one of] the homes to [the yard].54As apparent from the following clause, this applies when the yard was enclosed before an entrance leading to one of the homes was opened.
The Ramah (Orach Chayim 359:1) rules that the restriction mentioned in this law does not apply at present, since it has become customary to use our back yards. Hence, we assume that they were enclosed for the purpose of habitation.

If one opens an entrance [from one of the homes] to [the yard] and then encloses it, [the yard] is considered as enclosed for the purpose of habitation, and we are permitted to carry throughout its total [area].55Eruvin 24a states that this leniency applies even when a portion of the yard is used as a threshing floor. Since the person enclosed the area after opening an entrance to his home, we assume that the yard's primary purpose is to serve the home.

הלכה יא
רְחָבָה הַפְּתוּחָה לַמְּדִינָה מִצַּד אֶחָד וּמִצַּד אַחֵר פְּתוּחָה לַשְּׁבִיל הַמַּגִּיעַ לַנָּהָר. עוֹשֶׂה לָהּ לֶחִי מִצַּד הַמְּדִינָה וְיִהְיֶה מֻתָּר לְטַלְטֵל בְּכֻלָּהּ וּמִתּוֹכָהּ לַמְּדִינָה וּמִן הַמְּדִינָה לְתוֹכָהּ:
כסף משנה
11.
[Permission is granted to carry within] a yard56The yard is larger than 5000 square meters and was enclosed for purposes other than habitation (Rashi, Eruvin 24b). that opens to a city at one side and a path that leads to a river on the other [in the following manner]:57The Rambam's decision is based on the description of such a yard in Eruvin 24b. If one erects a post58Using a post, a lechi, as a divider is discussed in Chapter 17, Halachot 2 and 9.
As the Rambam mentions there, the post is considered as a fourth wall. In this instance, by erecting the post, one will be considered as erecting a new wall to enclose the yard for the sake of habitation (Rashi, loc. cit.).
at the side near the city, it is permitted to carry within [the yard], from [the yard] to the city,59This refers to a city surrounded by a wall, which is considered to be a private domain. and from the city to [the yard].

הלכה יב
יָחִיד שֶׁשָּׁבַת בְּבִקְעָה וְעָשָׂה מְחִצָּה סָבִיב לוֹ אִם יֵשׁ בָּהּ עַד בֵּית סָאתַיִם מֻתָּר לְטַלְטֵל בְּכֻלָּהּ. וְאִם הָיְתָה יֶתֶר עַל בֵּית סָאתַיִם אֵינוֹ מְטַלְטֵל בָּהּ אֶלָּא בְּאַרְבַּע אַמּוֹת. וְכֵן אִם הָיוּ שְׁנַיִם. אֲבָל שְׁלֹשָׁה יִשְׂרְאֵלִים אוֹ יֶתֶר עֲלֵיהֶן שֶׁשָּׁבְתוּ בְּבִקְעָה הֲרֵי הֵן שַׁיָּרָא וּמֻתָּר לָהֶם לְטַלְטֵל בְּכָל צָרְכָּן אֲפִלּוּ כַּמָּה מִילִין. וְהוּא שֶׁלֹּא יִשָּׁאֵר מִן הַמְּחִצָּה שֶׁהִקִּיפוּ בֵּית סָאתַיִם פָּנוּי בְּלֹא כֵּלִים. אֲבָל אִם נִשְׁאָר בֵּית סָאתַיִם פָּנוּי בְּלֹא כֵּלִים וְלֹא הָיוּ צְרִיכִים לוֹ אֲסוּרִים לְטַלְטֵל בְּכָל הַמְּחִצָּה אֶלָּא בְּאַרְבַּע אַמּוֹת. וְאֵין הַקָּטָן מַשְׁלִים לְשַׁיָּרָא:
כסף משנה
12.
[The following rules apply when] an individual spends the Sabbath in an open valley and constructs a partition60This refers even to an inferior partition, such as those mentioned in Halachah 18. Rashi (Eruvin 16b, the source for this halachah) states that the restrictions of this law apply only when the enclosure uses such an inferior partition. If a proper partition is erected, one may carry within the entire enclosure, since the enclosure was erected for the purpose of habitation. Note the Merkevet HaMishneh, who emphasizes that the Rambam does not accept this leniency.
The wording of the Shulchan Aruch and the Beit Yosef (Orach Chayim 360:1) appears to concur with Rashi's view. The later authorities also accept his ruling.
around his [immediate area]: If [the enclosed area] is the size of the area in which two seah [of grain can be sown] or less, he may carry within the entire [enclosed area]. If [the enclosed area] is larger, he may carry only within [a square of] four cubits.61Since the area is so large and it is enclosed only for a temporary period, the Sages placed restrictions on carrying within it.
It must, however, be emphasized that according to Torah law, the enclosure is considered a private domain. Accordingly, a person who carries from it to a public domain or from a public domain to it is liable (Shulchan Aruch HaRav 360:1; Mishnah Berurah 360:5).

The same [rules apply when] two individuals [spend the Sabbath in an open valley]. When, however, three or more Jews62With this term, the Rambam excludes a gentile. The Ramah (loc. cit.) also rules that a gentile may not be included in a caravan. spend the Sabbath in an open valley [and erect a partition enclosing their immediate area], they are considered a caravan and they are allowed to carry as far as necessary,63According to Torah law, such an area is a private domain. The Rabbis did not place any restrictions upon it, because it has - albeit temporarily - been enclosed for the purpose of habitation. even several millim, provided there is not a space larger than the area [necessary to sow] two seah left vacant without utensils. If, however, [the enclosed area] includes a space larger than the area [necessary to sow] two seah that is left vacant without utensils, and that is of no use to them,64See Shulchan Aruch HaRav 360:2, which mentions that it is acceptable if the land is used for pasture. they are allowed to carry only within [a square of] four cubits within the enclosure.65Since the enclosure includes such a large empty space, our Sages forbade carrying within it.
Based on the Mordechai, the Shulchan Aruch mentions a further leniency: If three people spend the Sabbath in an enclosure whose area is less than 18,000 square cubits, they are allowed to carry without restriction. The rationale is: Each individual is granted 5000 square cubits. Thus, there are less than 5000 square cubits that are not accounted for. This leniency is not, however, accepted by the other authorities.

A minor66The Jerusalem Talmud (Eruvin 1:10) does not resolve the question whether or not to count a child as a member of the caravan. In his Beit Yosef (loc. cit.), Rav Yosef Karo questions the Rambam's decision, for generally we follow the rule that when a doubt exists pertaining to a question of Rabbinic law, the more lenient view should be followed. Accordingly, he does not mention the matter in his Shulchan Aruch. The Ramah cites the Rambam's view, but prefaces it with the phrase "There are those who maintain," which implies that the opinion cited is not accepted universally. is not included in [the reckoning of the minimum number of people necessary to compose] a caravan.

הלכה יג
שְׁלֹשָׁה שֶׁהִקִּיפוּ כְּדֵי צָרְכָּן וְקָנוּ שְׁבִיתָה וְאַחַר כָּךְ מֵת אֶחָד מֵהֶן הֲרֵי הֵם מֻתָּרִין לְטַלְטֵל בְּכֻלָּהּ. קָנוּ שְׁנַיִם שְׁבִיתָה בְּיֶתֶר מִבֵּית סָאתַיִם וְאַחַר כָּךְ בָּא לָהֶם שְׁלִישִׁי אֲסוּרִין לְטַלְטֵל אֶלָּא בְּאַרְבַּע אַמּוֹת כְּשֶׁהָיוּ קֹדֶם שֶׁיָּבוֹא זֶה. שֶׁהַשְּׁבִיתָה הִיא הַגּוֹרֶמֶת לֹא הַדִּיּוּרִין:
כסף משנה
13.
When three people enclose an area large enough for their needs67I.e., greater than 5000 square cubits. and establish this as their place for the Sabbath, [those who remain] are allowed to [continue] carrying within the entire [enclosure]68This leniency applies only on the Sabbath on which the person dies. On the following Sabbath, they are forbidden to carry unless they are joined by a third individual. despite the fact that one of them dies [on the Sabbath].
When [by contrast] two individuals establish [an enclosed area] larger than the space [necessary to sow] two seah [of grain] as their place for the Sabbath, they may carry only within four cubits despite the fact that a third person joins them [on the Sabbath]. [The rationale for both decisions is that the ruling] is determined by the manner in which the individuals establish [a site as] their place for the Sabbath [at the commencement of the Sabbath], and not on the number of people who are actually present [on the Sabbath day].69See a further expression of this principle in Hilchot Eruvin 3:25.

הלכה יד
שְׁלֹשָׁה מְקוֹמוֹת הַמֻּקָּפִין שֶׁלֹּא לְשֵׁם דִּירָה זֶה בְּצַד זֶה וּפְתוּחִים זֶה לָזֶה שְׁנַיִם הַחִיצוֹנִים רְחָבִים וְהָאֶמְצָעִי קָצָר שֶׁנִּמְצְאוּ לַשְּׁנַיִם הַחִיצוֹנִים פַּסִּין מִכָּאן וּמִכָּאן וְהָיָה יָחִיד בָּזֶה וְיָחִיד בָּזֶה וְיָחִיד בָּזֶה נַעֲשׂוּ כְּשַׁיָּרָא וְנוֹתְנִין לָהֶם כָּל צָרְכָּן. הָיָה הָאֶמְצָעִי רָחָב וּשְׁנַיִם הַחִיצוֹנִים קְצָרִים שֶׁנִּמְצָא הָאֶמְצָעִי בְּפַסִּין מִשְּׁנֵי רוּחוֹתָיו הֲרֵי הוּא מֻבְדָּל מִשְּׁנַיִם הַחִיצוֹנִים. לְפִיכָךְ אִם שָׁבַת יָחִיד בָּזֶה וְיָחִיד בָּזֶה וְיָחִיד בָּזֶה אֵין נוֹתְנִין לָהֶן כָּל צָרְכָּן אֶלָּא כָּל אֶחָד וְאֶחָד יֵשׁ לוֹ בֵּית סָאתַיִם בִּמְקוֹמוֹ. הָיָה יָחִיד בָּזֶה וְיָחִיד בָּזֶה וּשְׁנַיִם בָּאֶמְצָעִי אוֹ שְׁנַיִם בָּזֶה וּשְׁנַיִם בָּזֶה וְאֶחָד בָּאֶמְצָעִי נוֹתְנִין לָהֶן כָּל צָרְכָּן:
כסף משנה
14.
[Our Sages did not establish restrictions against carrying in the following instance:] Three areas that are enclosed for purposes other than habitation are located adjacent to each other, and lead70I.e., the middle enclosure does not have a wall, but is totally open on either side (Shulchan Aruch, Orach Chayim 360:3). The Shulchan Aruch, however, follows the interpretation of the Ritba, who requires the walls of the narrow courtyard to enter into the space of the wider courtyard. The Rambam, however, does not appear to make such a requirement. to each other. The two outer enclosures are wide, while the middle enclosure is narrow. Thus, there are barriers around the outer enclosures on either side. If [three people spend the Sabbath in this place,] one in each of these enclosures, [the three] are considered as a caravan,71Since the individuals in each of the outer courtyards are considered as sharing the space of the middle courtyard. and they are allowed to carry [wherever] necessary.72I.e., they may carry freely from one enclosure to another. Note the Shulchan Aruch (loc. cit.), which states that they must make an eruv to join their respective enclosures together. Similarly, the Shulchan Aruch mentions a more restrictive opinion, which allows the individuals to carry freely only when the outer enclosures are less than 5000 square cubits in size.
If the middle enclosure is wide, while the two outer enclosures are narrow, there are barriers around the middle enclosure on either side. [Thus,] it is considered separate. Therefore, [if three people spend the Sabbath in this place,] one in each of these enclosures, they are not allowed to carry without restriction.73I.e., the outer enclosures are considered to be distinct entities without any connection to each other. Thus it is not considered as if three people are spending the Sabbath in the same place. Instead, each one is allowed to carry within his own enclosure [provided it is smaller74The bracketed additions are based on the commentary of Rashi (Eruvin 93a, the source for this halachah) and the Shulchan Aruch (loc. cit.).than the space necessary to sow] two seah [of grain].
If a single individual [spends the Sabbath] in each [of the outer enclosures], while two people are in the middle enclosure, or two people [spend the Sabbath] in each [of the outer enclosures], while one person is in the middle enclosure, they are allowed to carry [wherever] necessary.75In both of these instances, three individuals share a single portion of space. Therefore, they are allowed to carry freely from one enclosure to another.

הלכה טו
כָּל מְחִצָּה שֶׁאֵינָהּ יְכוֹלָה לַעֲמֹד בְּרוּחַ מְצוּיָה אֵינָהּ מְחִצָּה. וְכָל מְחִצָּה שֶׁאֵינָהּ עֲשׂוּיָה לְנַחַת אֵינָהּ מְחִצָּה. וְכָל מְחִצָּה שֶׁאֵינָהּ עֲשׂוּיָה אֶלָּא לִצְנִיעוּת בִּלְבַד אֵינָהּ מְחִצָּה. וְכָל מְחִצָּה שֶׁאֵין בְּגָבְהָהּ עֲשָׂרָה טְפָחִים אוֹ יוֹתֵר אֵינָהּ מְחִצָּה גְּמוּרָה. גִּדּוּד חֲמִשָּׁה וּמְחִצָּה חֲמִשָּׁה מִצְטָרְפִין:
כסף משנה
15.
Any partition76In this halachah, the Rambam begins to describe the rules that govern the walls that enclose a private domain. The concepts he mentions are also relevant to the laws of sukkah and other contexts within Jewish law. that cannot stand in the face of an ordinary wind is not considered a significant partition.77I.e., it is as if the partition were not there. See notes below.
Rashi, Sukkah 24b, states that this applies not only when the wall will fall because of the wind, but also to a cloth wall that will blow back and forth. From Halachah 24, it appears that this ruling is also accepted by the Rambam. It is quoted by the Shulchan Aruch (Orach Chayim 362:1 and 630:10).
[Similarly,] any partition which is not constructed in a lasting manner78Our translation follows Rabbenu Chanan'el's text of Eruvin 26a. According to this interpretation, our Sages are teaching us that a partition must be constructed in a firm and sturdy fashion. (See also the interpretation of the term in the Aruch.) See also Halachah 12 and notes.
The Ra'avad, Rashi, and others follow a different text of the Talmud, which reads כל מחיצה העשויה לנח ת. According to this interpretation, this refers to a partition erected for storage purposes and not for people to dwell within. This latter view is quoted by the Shulchan Aruch (Orach Chayim 362:1).
is not considered a significant partition. [Likewise,] a partition constructed only for the purpose of modesty79The commentaries on Eruvin (loc. cit.) interpret this as a temporary partition that builders construct for shade. (Rav Kapach, however, cites interpretations of the Geonim that interpret the term "for the sake of modesty" literally, to change one's clothes behind.)
Thus, all three partitions mentioned in this halachah share the same drawback; they are not constructed in a lasting or sturdy manner.
In his gloss on this halachah, the Maggid Mishneh quotes the Rashba, who mentions that since all these partitions are valid according to Torah law, the expression "they are not partitions" must be interpreted as follows: They are not partitions constructed for the purpose of habitation. Therefore, if an area larger than 5000 square cubits is enclosed with such a partition, it is forbidden to carry within. If, however, an area less than 5000 square cubits is enclosed by such a partition, one may carry within. This opinion is quoted by the Tur and the Shulchan Aruch (loc. cit.).
The Lechem Mishneh, the Beit Yosef (Orach Chayim 362) and others maintain that the Rambam does not accept the Rashba's view. Kinat Eliyahu, however, notes that the fact that the Rambam mentions these laws directly after the laws concerning a karpef may have been intended to allude to the Rashba's concept.
is not considered a significant partition.
Any partition that is not ten handbreadths high is not considered to be a complete partition.80The Maggid Mishneh interprets the phrase "it is not a complete partition" to mean: It is not a partition significant enough to cause an enclosure to be considered to be a private domain. It may, however, cause an enclosure to be considered to be a carmelit. A mound81Our translation is based on the gloss of the Maggid Mishneh, which is quoted by the Shulchan Aruch (Orach Chayim 362:2).
See also the interpretation of Rabbenu Chanan'el to Eruvin 93b, which interprets it as a "rock." From a halachic perspective, these interpretations are not mutually exclusive. See Chapter 15, Halachah 9.
five handbreadths high and a partition [on top of it] five handbreadths [high] are combined [and together are considered to be a valid partition].

הלכה טז
כָּל מְחִצָּה שֶׁיֵּשׁ בָּהּ פָּרוּץ מְרֻבֶּה עַל הָעוֹמֵד אֵינָהּ מְחִצָּה. אֲבָל אִם הָיָה פָּרוּץ כְּעוֹמֵד הֲרֵי זוֹ מֻתֶּרֶת. וּבִלְבַד שֶׁלֹּא יִהְיֶה בְּאוֹתָן הַפְּרָצוֹת פִּרְצָה שֶׁהִיא יֶתֶר עַל עֶשֶׂר אַמּוֹת. אֲבָל עֶשֶׂר אַמּוֹת הֲרֵי הִיא כְּפֶתַח. אִם הָיָה לְפִרְצָה זוֹ צוּרַת פֶּתַח אַף עַל פִּי שֶׁיֵּשׁ בָּהּ יוֹתֵר מֵעֶשֶׂר אֵינָהּ מַפְסֶדֶת הַמְּחִצָּה. וְהוּא שֶׁלֹּא יְהֵא הַפָּרוּץ מְרֻבֶּה עַל הָעוֹמֵד:
כסף משנה
16.
Any partition whose open portion exceeds its closed portion is not considered to be a partition.82I.e., if a wall includes open spaces, the area that is open may not exceed the area that is enclosed. As mentioned in the following halachah, this refers to open spaces that are larger than three handbreadths wide. As the Rambam states in Halachah 18, this refers to spaces in the horizontal as well as the vertical portion of the wall. If, however, the open portion is equivalent to its closed portion, it is permitted [to carry within the enclosure], provided none of the open portions is larger than ten cubits wide.83I.e., when there is an open space larger than ten cubits wide, the entire partition is nullified. [The rationale for this leniency is that an open space] ten cubits [or less] is considered to be an entrance.84As long as the opening is ten cubits wide or less, there is no need to enclose it with a frame of an entrance. It is commonplace for a wall to have an entrance that is less than ten cubits wide without a frame.
If, however, this open space [is enclosed by] the frame of an entrance,85The Rambam explains the structure of a frame of an entrance (tzurat hapetach) in Halachah 19., even if it is wider than ten cubits the partition is not considered to be nullified,86I.e., by erecting the frame of an entrance, one enables a partition to be considered acceptable despite the fact that it has an opening that is larger than ten cubits. provided the open space does not exceed the closed portion.87This ruling represents a point of difference between the Rambam and most other authorities. According to the Rambam, although the frame of an entrance enables an opening larger than ten cubits to be accepted, the opening is still considered an open space. Accordingly, if the total amount of open space on any one side of a partition exceeds the closed space, the partition is unacceptable, even though portions of the open space possess a frame of an entrance.
Many authorities (e.g., the Rashba and Tosafot, Eruvin 11a) differ and maintain that once a frame of an entrance is constructed, the space below it is deemed closed and should be considered as such when calculating whether the enclosed portion of a partition exceeds its open area. The opinion of these authorities is accepted by the Shulchan Aruch (Orach Chayim 362:10). Nevertheless, Shulchan Aruch HaRav 362:19 and the Mishnah Berurah 362:59 state that it is proper to be stringent and follow the Rambam's ruling.
Rabbenu Asher cites the Jerusalem Talmud (Eruvin 1:9) and Kilayim 4:2 as the source for the Rambam's ruling. (See also Hilchot Shofar V'Sukkah V'Lulav 4:12, where the Rambam accepts a more lenient view regarding the walls of a sukkah. Note also the glosses of the Kessef Mishneh and the Maggid Mishneh there.)
See also the commentary of Rav Kapach, who advances an interpretation of the Rambam's statements here and in his Commentary on the Mishnah (Eruvin 1:8) that maintains that the Rambam follows the view advanced by the Rashba. Even those who reject this interpretation in most instances are forced to accept it with regard to the third side of an alley, as stated in Chapter 17, Halachah 3. (Note also Chapter 17, Halachah 27.)
The difference between the Rambam's ruling and that of the other authorities is particularly relevant in contemporary communities that permit carrying because of an eruv. Most of these communities are enclosed, not by a proper wall, but by a series of "frames of an entrance" constructed using telephone poles and the like. According to the Rambam, these enclosures are not acceptable. Indeed, this is one of the reasons why the carefully observant refrain from carrying in these communities.

הלכה יז
בַּמֶּה דְּבָרִים אֲמוּרִים בִּזְמַן שֶׁהַפְּרָצוֹת מִשְּׁלֹשָׁה טְפָחִים וּלְמַעְלָה. אֲבָל אִם הָיוּ הַפְּרָצוֹת כָּל פִּרְצָה מֵהֶן פְּחוּתָה מִשְּׁלֹשָׁה הֲרֵי זוֹ מֻתֶּרֶת. וְאַף עַל פִּי שֶׁהַפָּרוּץ מְרֻבֶּה עַל הָעוֹמֵד. שֶׁכָּל פָּחוֹת מִשְּׁלֹשָׁה הֲרֵי הוּא כְּלָבוּד:
כסף משנה
17.
When does the above apply? When the open spaces are three handbreadths or wider. If, however, the open spaces are each less than three handbreadths,88More precisely, the same ruling applies if some of the spaces are wider than three handbreadths, as long as the size of the total of the open spaces wider than three handbreadths does not exceed the remainder of the partition. the partition is acceptable although the total open space exceeds the space which is enclosed. For whenever there is an opening of less than three handbreadths, the portions separated in this manner are considered as parts of a solid partition.

הלכה יח
כֵּיצַד. הֲרֵי שֶׁהִקִּיף בְּקָנִים וְאֵין בֵּין קָנֶה לַחֲבֵרוֹ שְׁלֹשָׁה טְפָחִים. אוֹ שֶׁהִקִּיף בַּחֲבָלִים וְאֵין בֵּין חֶבֶל לַחֲבֵרוֹ שְׁלֹשָׁה טְפָחִים. הֲרֵי זוֹ מְחִצָּה גְּמוּרָה. אַף עַל פִּי שֶׁהִיא שְׁתִי בְּלֹא עֵרֶב אוֹ עֵרֶב בְּלֹא שְׁתִי. וְצָרִיךְ שֶׁיִּהְיֶה גֹּבַהּ הַקָּנֶה עֲשָׂרָה אוֹ שֶׁיִּהְיֶה מִן הָאָרֶץ עַד סוֹף עֹבִי הַחֶבֶל הָעֶלְיוֹן עֲשָׂרָה אִם הִקִּיף בַּחֲבָלִים. שֶׁאֵין מְחִצָּה פְּחוּתָה מֵעֲשָׂרָה. וְכָל הַשִּׁעוּרִין הָאֵלּוּ הֲלָכָה לְמשֶׁה מִסִּינַי הֵן:
כסף משנה
18.
What does the above imply? For example, a person makes an enclosure with reeds - as long as there is less than three handbreadths between one reed and the next, the partition is fully acceptable. Similarly, if one makes a partition with ropes, as long as there is less than three handbreadths between one rope and the next [the partition is fully acceptable]. [The above applies] even when the [reeds or ropes] run vertically but not horizontally,89As the Rambam continues, a partition of reeds will generally be constructed by implanting them upright in the ground, one near the other. As long as the reeds are not three handbreadths apart, the partition is acceptable even if there are no reeds that run horizontally. or horizontally but not vertically.90Generally, a partition of ropes will be constructed by stretching them from one post to another. As long as the ropes are not three handbreadths apart, the partition is acceptable, even if there are no ropes that run vertically.
The height of the reeds must be at least ten [handbreadths], or there must be ten handbreadths from the earth to the top of the highest rope if one makes an enclosure with rope. For a partition cannot be less than ten handbreadths high. All these measures are part of the oral tradition transmitted to Moses on Mount Sinai.91In the Introduction to his Commentary on the Mishnah, the Rambam defines the Hebrew term halachah l'Mosheh miSinai as referring to laws that have no obvious source in the Written Torah, yet have been accepted throughout the centuries as an integral part of the Torah tradition.

הלכה יט
צוּרַת פֶּתַח הָאֲמוּרָה בְּכָל מָקוֹם הִיא אֲפִלּוּ קָנֶה וְכַיּוֹצֵא בּוֹ מִכָּאן וְקָנֶה מִכָּאן וְקָנֶה עַל גַּבֵּיהֶן. גֹּבַהּ שְׁנֵי הַלְּחָיַיִם עֲשָׂרָה טְפָחִים אוֹ יֶתֶר וְהַקָּנֶה וְכַיּוֹצֵא בּוֹ שֶׁעַל גַּבֵּיהֶן אַף עַל פִּי שֶׁאֵינוֹ נוֹגֵעַ בִּשְׁנֵי הַלְּחָיַיִם אֶלָּא יֵשׁ בֵּינֵיהֶן כַּמָּה אַמּוֹת הוֹאִיל וְגֹבַהּ הַלְּחָיַיִם עֲשָׂרָה הֲרֵי זוֹ צוּרַת פֶּתַח. וְצוּרַת פֶּתַח שֶׁאָמְרוּ צְרִיכָה שֶׁתְּהֵא בְּרִיאָה לְקַבֵּל דֶּלֶת אֲפִלּוּ דֶּלֶת שֶׁל קַשׁ:
כסף משנה
19.
Whenever the term "frame of an entrance" is mentioned, it refers to a structure that has at the very least one reed at either side and another reed above them.92As the Shulchan Aruch (Orach Chayim 362:11) emphasizes, the reed must be placed exactly above the two side posts. It is not acceptable for it to be attached to their sides, for then it does not resemble the lintel of a doorway. [There is a further leniency:] The height of the posts at the sides must be at least ten handbreadths, but it is not necessary for the reed or other material placed above them to touch them. Even if it is several cubits above them,93In his gloss on this halachah, Rabbi Akiva Eiger explains that this is acceptable because of the principle gud asik - i.e., the posts at the side are considered to be extended until they reach the crossbar. Based on this rationale, it follows that the two posts need not be of the same height. Even if one is higher than the other, they may still be considered as part of the same frame of an entrance. (Note also the application of this principle in Hilchot Sukkah 4:2.) since the posts at the side are ten [handbreadths] high, [the structure] is considered to be a frame of an entrance.
The frame of an entrance mentioned94According to the Shulchan Aruch (loc. cit.), this refers to the posts on the side. The crossbar above need not be sturdy at all. must be sturdy enough to hold a door.95The Rambam's decision is based on Eruvin 11b. His ruling, however, has aroused questions. The passage cited also mentions opinions that require the post to have a hinge for the door on at least one side. Although there are authorities who also accept the latter requirement, the Shulchan Aruch (loc. cit.) follows the Rambam's view. Nevertheless, [the door need not be of a heavy substance;] a door of straw is also sufficient.

הלכה כ
פָּתַח שֶׁצּוּרָתוֹ כִּפָּה אִם יֵשׁ בְּאֹרֶךְ רַגְלֵי הַכִּפָּה עֲשָׂרָה טְפָחִים הֲרֵי זֶה צוּרַת פֶּתַח. וְצוּרַת פֶּתַח שֶׁעָשָׂה אוֹתָהּ מִן הַצַּד אֵינָהּ כְּלוּם שֶׁאֵין דֶּרֶךְ הַפְּתָחִים לִהְיוֹת בְּקֶרֶן זָוִית אֶלָּא בְּאֶמְצַע:
כסף משנה
20.
When the upright portions of the sides of an entrance that is structured in the form of an arch are ten [handbreadths] high,96I.e., the circular portion of the arch is not counted in the calculation of the entrance's height.
The commentaries draw attention to the Rambam's decision in Hilchot Mezuzah 6:4, where he also requires an arched doorway to have doorposts ten handbreadths high in addition to the arch, for the doorway to need a mezuzah. There is, however, a difference - and somewhat of a divergence - between the rationales the Rambam gives in both sources.
it is considered to be a "frame of an entrance."
A frame of an entrance that is constructed at the side of a partition97I.e., there is an opening of more than ten cubits at the corner where two walls would merge if they were continued. Even if one constructs a frame of an entrance at this opening, it is not acceptable. (See the Rambam's Commentary on the Mishnah, Eruvin 9:3.)
It must be noted that in their commentaries on Eruvin 11b, the source for this halachah, Rashi and the Rashba interpret the passage as referring, not to an entrance constructed at the corner of a wall, but to a lintel, projecting from the side of a doorpost. As mentioned in Halachah 19, the requirement for a frame of an entrance is for the lintel to be above the door posts and not projecting from their sides (Kessef Mishneh).
is not significant, for it is not common for entrances to be constructed at the corner [of a wall],98Note Chapter 17, Halachah 35, which mentions another law based on this same principle. but rather in its center.

הלכה כא
בַּכּל עוֹשִׂין מְחִצָּה בֵּין בְּכֵלִים בֵּין בָּאֳכָלִים בֵּין בְּאָדָם אֲפִלּוּ בִּבְהֵמָה וּשְׁאָר מִינֵי חַיָּה וְעוֹף וְהוּא שֶׁיִּהְיוּ כְּפוּתִים כְּדֵי שֶׁלֹּא יָנוּדוּ:
כסף משנה
21.
A partition may be made from any substances:99See parallels in Chapter 17, Halachah 12, and Hilchot Sukkah 4:16. utensils, food stuffs, or human beings.100Unlike the animals that the Rambam proceeds to mention, a human being need not be bound, as is obvious from Halachah 23. Even livestock101If the animal is standing and there are three handbreadths b etween the animal's body and the ground, that space must be filled with other substances (Shulchan Aruch HaRav 362:12). and other animals and birds [may be used for this purpose] provided they are bound102Note that in Hilchot Sukkot (loc. cit.), the Rambam does not require that animals be bound when they serve as part of a wall. The Shulchan Aruch (Orach Chayim 630:11) states that the animals must be bound even when used for the purpose of a sukkah's wall. so that they will not depart.

הלכה כב
מְחִצָּה הָעוֹמֶדֶת מֵאֵלֶיהָ הֲרֵי זוֹ כְּשֵׁרָה. וּמְחִצָּה הַנַּעֲשֵׂית בְּשַׁבָּת הֲרֵי זוֹ מְחִצָּה. וְאִם נַעֲשֵׂית בִּשְׁגָגָה מֻתָּר לְטַלְטֵל בָּהּ בְּאוֹתָהּ שַׁבָּת. וְהוּא שֶׁתֵּעָשֶׂה שֶׁלֹּא לְדַעַת הַמְּטַלְטֵל. אֲבָל אִם נִתְכַּוֵּן אָדָם לְזוֹ הַמְּחִצָּה שֶׁתֵּעָשֶׂה בְּשַׁבָּת כְּדֵי לְטַלְטֵל בָּהּ אַף עַל פִּי שֶׁעָשָׂה אוֹתָהּ הָעוֹשֶׂה בִּשְׁגָגָה אָסוּר לְטַלְטֵל בָּהּ בְּאוֹתָהּ שַׁבָּת. וְכֵן אִם נַעֲשֵׂית בְּמֵזִיד אַף עַל פִּי שֶׁלֹּא נִתְכַּוֵּן זֶה לְטַלְטֵל בָּהּ הֲרֵי זֶה אָסוּר לְטַלְטֵל בָּהּ:
כסף משנה
22.
A partition that arises on its own accord103The Shulchan Aruch (Orach Chayim 362:3) explains this as referring to a structure that was not built with the intent of enclosing an area, but accomplished that purpose nonetheless. is acceptable. Similarly, a partition that is erected on the Sabbath is considered to be a partition.104I.e., in all instances, the partition is considered valid, and the enclosure is considered a private domain. Therefore, a person who transfers an article into this enclosure from the public domain is liable. Our Sages, however, placed certain restrictions on carrying within such an enclosure, as the Rambam continues to explain. If it is constructed unintentionally, carrying within [the enclosed area] is permitted on that Sabbath,105I.e., the person who constructed the partition did so without knowing that it was the Sabbath or without knowing that it is forbidden to build on the Sabbath (Mishnah Berurah 362:18). provided it is not constructed with the knowledge of those who carry within.
If, however, a person intends that a partition be erected on the Sabbath, he is forbidden to carry within [the enclosure] on that Sabbath, even though the person who actually constructed the partition did not do so with the intent of violating [the Sabbath laws].106According to the Chemed Mosheh, this refers to a situation in which one person had another construct an enclosure for the former to carry within on the Sabbath. Although the person who actually constructed the enclosure did not intend to violate the Sabbath laws, the person for whom he performed the labor desired that such a violation take place. Hence, that person is prohibited from carrying within. This explanation resolves the question raised by the Rashba that is quoted by the Maggid Mishneh. Similarly, if [a partition] is erected with a conscious intent to violate [the Sabbath laws], it is forbidden to carry within [the enclosure]107As mentioned in the notes on Chapter 6, Halachah 23, when a Jew intentionally performs a forbidden labor on the Sabbath, it is forbidden for other Jews to benefit from that labor on that Sabbath itself. The person who performed the labor, by contrast, is never permitted to benefit from it. Thus, in this instance, he would be forbidden from ever carrying within this enclosure on the Sabbath. (See Or Sameach.)
Note the Shulchan Aruch (loc. cit.), which states that if a partition had been standing before the Sabbath, it was removed on the Sabbath and then reconstructed on the Sabbath, it is permitted to carry within the enclosure. This applies even if the partition was rebuilt intentionally on the Sabbath. The Mishnah Berurah 362:26, however, cites authorities that do not accept this leniency.
even if [the person who erected the structure] did not intend to carry within it.

הלכה כג
מֻתָּר לַעֲשׂוֹת מְחִצָּה שֶׁל בְּנֵי אָדָם בְּשַׁבָּת שֶׁיַּעֲמֹד זֶה בְּצַד זֶה וּבִלְבַד שֶׁלֹּא יֵדְעוּ אֵלּוּ הָעוֹמְדִין שֶׁבִּשְׁבִיל לַעֲשׂוֹתָן מְחִצָּה הֶעֱמִידָן. וְלֹא יַעֲמִיד אוֹתָן אָדָם שֶׁהוּא רוֹצֶה לְהִשְׁתַּמֵּשׁ בִּמְחִצָּה זוֹ אֶלָּא יַעֲמִיד אוֹתָן אַחֵר שֶׁלֹּא לְדַעְתּוֹ:
כסף משנה
23.
It is permitted to erect a human partition on the Sabbath - i.e., people standing next to each other108I.e., within three handbreadths of each other (Shulchan Aruch, Orach Chayim 362:5). Note the Bayit Chadash (Orach Chayim 362) and the Be'ur Halachah 362, which question why the people may not be even further separated. - provided that the people whose bodies form the partition do not know that they are standing there for that purpose.109Although constructing a partition of this nature is not considered as building, it is still forbidden for the people who stand there to have in mind that their bodies serve as an enclosure, lest they come to treat the Sabbath prohibitions lightly (Mishnah Berurah 362:39). Nor may the person who desires to use this enclosure be the one who has them stand there.110The Rashba differs with this ruling and maintains that there is no difficulty if the person who desires to use the enclosure has the people stand there. According to his opinion, the only difficulty is when the people forming the partition have such an intent. The Shulchan Aruch (Orach Chayim 362:7) prefaces the quotation of the Rambam's ruling with the words, "There is one who says," which implies that it is not accepted by all. Similarly, the later authorities do not obligate compliance with this stringency.
Significantly, when discussing the use of human beings as part of the wall of a sukkah on the holiday, the Rambam (Hilchot Sukkah 4:16) states that the people serving as the wall may not know that their bodies are being used in that capacity, but the person sitting in the sukkah may have that intent.
Instead, another person should have them stand there without the knowledge of [the person who will benefit from the enclosure].111Note the Ramah (Orach Chayim 362:7), who states that the leniency of using human beings to form an enclosure on the Sabbath should be employed only in a very extreme situation. He maintains that it is preferable to have a child bring in an article from the public domain without making an enclosure, rather than to have an adult carry the article in within an enclosure consisting of human beings. Although the later authorities raise questions regarding employing a child for this purpose, they accept the Ramah's hesitation about using an enclosure of human bodies.

הלכה כד
אִילָן שֶׁהוּא מֵסֵךְ עַל הָאָרֶץ אִם אֵין נוֹפוֹ גָּבוֹהַּ מִן הָאָרֶץ שְׁלֹשָׁה טְפָחִים מְמַלֵּא בֵּין בָּדָיוֹ וְעָלָיו תֶּבֶן וְקַשׁ וְכַיּוֹצֵא בָּהֶן וְקוֹשְׁרָן בָּאָרֶץ עַד שֶׁיַּעֲמֹד בְּרוּחַ מְצוּיָה וְלֹא יִתְנַדְנֵד וּמְטַלְטֵל תַּחַת כֻּלּוֹ. וְהוּא שֶׁיִּהְיוּ תַּחְתָּיו עַד בֵּית סָאתַיִם. אֲבָל אִם הָיָה יֶתֶר מִבֵּית סָאתַיִם אֵין מְטַלְטְלִין תַּחְתָּיו אֶלָּא בְּאַרְבַּע אַמּוֹת מִפְּנֵי שֶׁתַּחְתָּיו מָקוֹם שֶׁלֹּא הֻקַּף לְדִירָה הוּא:
כסף משנה
24.
The branches of a tree which hang downward and which reach within three handbreadths of the earth [may serve as an enclosure].112For this rule to apply, there must be a place four handbreadths by four handbreadths in area and ten handbreadths high beneath the tree. Otherwise, the space is considered as a carmelit (Shulchan Aruch HaRav 362:2; Mishnah Berurah 362:5). One should place straw, stubble, and the like between the branches and the leaves, and should tie them to the earth so that they will stand firmly and not flutter in the face of an ordinary wind.113See Halachah 15. (See also Hilchot Sukkah 4:5, where the Rambam mentions similar concepts with regard to using a tree as a wall for a sukkah.) [When this is done,] one may carry under the entire [tree].
[The above applies] when there is less than the space [necessary to sow] two seah [of grain beneath the tree]. If, however, the area [below the tree] is larger than that, we are allowed to carry only within four cubits [in this space], since the space beneath [the tree] was enclosed for purposes other than dwelling.114As mentioned at the beginning of the chapter, when an area was enclosed for purposes other than habitation, one may not carry within it, if it is larger than the space necessary to sow two seah of grain - i.e., 5000 square cubits.

זמנים הלכות שבת פרק טז
Zemanim Shabbos Chapter 16