Halacha

הלכה א
הַמְקַבֵּל עָלָיו לִהְיוֹת נֶאֱמָן עַל הַמַּעַשְׂרוֹת וְלֹא יִהְיוּ פֵּרוֹתָיו דְּמַאי צָרִיךְ לִהְיוֹת מְעַשֵּׂר אֶת שֶׁהוּא אוֹכֵל וְאֶת שֶׁהוּא מוֹכֵר וְאֶת שֶׁהוּא לוֹקֵחַ. וְאֵינוֹ מִתְאָרֵחַ אֵצֶל עַם הָאָרֶץ. וְצָרִיךְ שֶׁיְּקַבֵּל עָלָיו דְּבָרִים אֵלּוּ בָּרַבִּים. וּכְשֶׁיָּבוֹאוּ עֵדִים נֶאֱמָנִין שֶׁקִּבֵּל דְּבָרִים אֵלּוּ בָּרַבִּים וְשֶׁהוּא רָגִיל בָּהֶם תָּמִיד הֲרֵי זֶה נֶאֱמָן עַל פֵּרוֹתָיו לוֹמַר מְעֵשָּׂרִין הֵן:
כסף משנה
1.
When a person makes a commitment to be considered trustworthy1Such a person is called a chavair. In his Commentary to the Mishnah (Demai 2:3), the Rambam explains that this term is used because, as indicated by the following halachah, the term refers to Torah scholars. Chavair means "friend." This term is appropriate to be used with regard to Torah scholars, because since their friendship is based on the Torah, it is true friendship, for its motivation is for the sake of heaven. with regard to the tithes [so that] his produce will not be considered as demai, he must tithe [the produce] he eats,2Whether his own produce or produce he is given by others. that which he sells, and that which he purchases,3Both produce that he purchases for his own consumption and that which he purchases for commercial purposes. and he must not accept the hospitality of a common person. He must make these commitments in public.4From Hilchot Tumat Mishkav UMoshav 10:5, it appears that he must make these statements in the presence of three people who are themselves considered as trustworthy in this regard. When trustworthy witnesses5I.e., witnesses who meet the criteria for acceptable witnesses spelled out in Hilchot Edut. [testify] that he made these commitments in public and that he continually observe these practices, he is considered trustworthy [and his word is accepted if] he says that his produce has been tithed.

הלכה ב
כָּל תַּלְמִיד חָכָם לְעוֹלָם נֶאֱמָן וְאֵינוֹ צָרִיךְ בְּדִיקָה אַחֲרָיו. וּבָנָיו וּבְנֵי בֵּיתוֹ וַעֲבָדָיו [וְאִשְׁתּוֹ] הֲרֵי הֵם כָּמוֹהוּ. תַּלְמִיד חָכָם שֶׁמֵּת וְהִנִּיחַ פֵּרוֹת אֲפִלּוּ כְּנָסָם בְּאוֹתוֹ הַיּוֹם הֲרֵי הֵן בְּחֶזְקַת מְתֻקָּנִין:
כסף משנה
2.
Every Torah scholar is always considered trustworthy. There is no necessity to investigate his [conduct]. His children, the members of his household, his servants, and his wife, are given the same status. When a Torah scholar dies and leaves produce, even if it was gathered on the day of his death, we assume that [the appropriate separations were made].6I.e., we assume that he separated the tithes from the produce before he died, for "We can presume that a chavair will not release anything from under his hand unless the appropriate separations have been made" (Pesachim 9a).

הלכה ג
בַּת עַם הָאָרֶץ אוֹ אִשְׁתּוֹ שֶׁנִּסֵּת לְחָבֵר וְעַבְדּוֹ שֶׁנִּמְכָּר לְחָבֵר צְרִיכִין לְקַבֵּל עֲלֵיהֶם בַּתְּחִלָּה. וּבַת חָבֵר אוֹ אִשְׁתּוֹ שֶׁנִּסֵּת לְעַם הָאָרֶץ וְעַבְדּוֹ שֶׁנִּמְכָּר לְעַם הָאָרֶץ הֲרֵי הֵן בְּחֶזְקָתָן עַד שֶׁיֵּחָשְׁדוּ. בְּנוֹ אוֹ עַבְדּוֹ שֶׁל חָבֵר שֶׁהָיוּ לְמוּדִין אֵצֶל עַם הָאָרֶץ צְרִיכִין לְקַבֵּל. בְּנוֹ אוֹ עַבְדּוֹ שֶׁל עַם הָאָרֶץ שֶׁהָיוּ לְמוּדִים אֵצֶל חָבֵר כָּל זְמַן שֶׁהֵן אֶצְלוֹ הֲרֵי הֵן כְּחָבֵר. יָצְאוּ הֲרֵי הֵן כְּעַם הָאָרֶץ:
כסף משנה
3.
When the daughter of a common person or his wife7I.e., after she is divorced or widowed from the common person. marries a chavair or the servant8I.e., a Canaanite servant, for a Jewish servant is not sold to another master (Hilchot Avadim 4:10). [of a common person] was sold to a chavair, they must accept the [above] requirements as at the outset.9I.e., if a woman or servant does not have a history of non-observance, it is assumed that when they become part of a chavair's home, they will accept the standards of the home. In this instance, however, because they have a history of non-observance, they must formally accept the chavair's standards. When the daughter of a chavair or his wife marries a common person or the servant [of a chavair] was sold to a common person, we assume that they maintain their observance10This applies even when they are in the common person's domain. until they act in a manner that arouses suspicion. A son or a servant of a chavair who would frequently visit a common person must formally accept [the above requirements].11I.e., since he freely associates with the common people, we suspect that he has accepted certain dimensions of their lifestyle. When a son or a servant of a common person would frequently visit a chavair, as long as he is in his domain, he is considered like a chavair. When he departs, he is considered as a common person.12Rambam LeAm compares the final two clauses of this halachah and draws an ethical lesson. It is more likely that a person with proper habits will become lax due to the bad habits of a friend than a person with improper habits will change to the better due a friend's positive influence.

הלכה ד
מִי שֶׁאֵינוֹ נֶאֱמָן וְהָיָה אֶחָד מִבָּנָיו אוֹ מֵעֲבָדָיו נֶאֱמָן אוֹ אֶחָד מִמִּשְׁפַּחְתּוֹ לוֹקְחִין מִמֶּנּוּ וְאוֹכְלִין עַל פִּיהֶן וְאֵינָן חוֹשְׁשִׁין לְדָבָר:
כסף משנה
4.
When a person himself is not considered as trustworthy, but one of his sons or servants or another member of his family is, food may be taken from him based on their statements.13I.e., if they state that the appropriate separations have been made from the produce, we accept their word. We do not harbor suspicions concerning the matter.

הלכה ה
הָיָה הוּא נֶאֱמָן וְאִשְׁתּוֹ אֵינָהּ נֶאֱמֶנֶת לוֹקְחִים מִמֶּנּוּ וְאֵין מִתְאָרְחִין אֶצְלוֹ. [הָיְתָה אִשְׁתּוֹ נֶאֱמֶנֶת וְהוּא אֵינוֹ נֶאֱמָן מִתְאָרְחִין אֶצְלוֹ וְאֵין לוֹקְחִין מִמֶּנּוּ. וְתָבוֹא מְאֵרָה לְמִי שֶׁאִשְׁתּוֹ נֶאֱמֶנֶת וְהוּא אֵינוֹ נֶאֱמָן]:
כסף משנה
5.
If a person was considered trustworthy, but his wife was not considered trustworthy,14The Jerusalem Talmud (Demai 2:2) compares this to dwelling with a snake in its den. we may purchase produce from him,15For the sale of produce will be under his direct supervision. but we do not accept his hospitality. If his wife is trustworthy and he is not, we may accept his hospitality, but we do not purchase produce from him. May a curse be visited on one whose wife is trustworthy, but he is not.

הלכה ו
לֹא יְשַׁמֵּשׁ חָבֵר לֹא בְּמִשְׁתֵּה עַם הָאָרֶץ וְלֹא בִּסְעֻדָּתוֹ אֶלָּא אִם כֵּן הָיָה הַכּל מְעֻשָּׂר וּמְתֻקָּן מִתַּחַת יָדוֹ. לְפִיכָךְ הָרוֹאֶה חָבֵר מְשַׁמֵּשׁ בְּמִשְׁתֵּה עַם הָאָרֶץ אוֹ בִּסְעֻדָּתוֹ הֲרֵי הַכּל בְּחֶזְקַת מְתֻקָּן וּמְעֻשָּׂר. רָאוּהוּ מֵסֵב עִם עַמֵּי הָאָרֶץ אֵין הַסְּעֻדָּה בְּחֶזְקַת מְעֻשֶּׂרֶת. שֶׁמָּא הֶחָבֵר עַל הַתְּנָאִים שֶׁבְּלִבּוֹ הוּא סוֹמֵךְ:
כסף משנה
6.
A chavair should not serve as a waiter at a drinking party or a feast of a common person unless all [the food and drink] have been tithed and the appropriate separations made under his supervision.16I.e., he cannot rely on the common person's word that the separations have been made. He must supervise the separations himself. Therefore if one sees a chavair serving at a drinking party or a feast of a common person, he can operate under the presumption that the tithes and other separations have been made.17To cite a contemporary application of this concept: If one sees a mashgiach, kashrut supervisor, in a restaurant, one may assume that the food is kosher.
If we see such a person eating together with a common person, we cannot assume that the food served at the feast has been tithed. Perhaps the chavair is relying on the stipulations made in his heart.18As explained in Chapter 9, Halachot 7-11, a chavair may eat at a common person's home and separate the tithes by leaving over portions of food. He separates the tithes for his portion alone and not for all the food served. If he is serving the meal, the responsibility for the kashrut of the food is his. If he is merely dining, he has no general responsibility as stated in the following halachah.

הלכה ז
כְּשֵׁם שֶׁאָדָם סוֹעֵד אֵצֶל עַם הָאָרֶץ וְסוֹמֵךְ עַל תְּנָאוֹ כָּךְ הוּא צָרִיךְ לִהְיוֹת מַתְנֶה עַל בְּנוֹ וַאֲפִלּוּ הָיָה בְּנוֹ בְּמָקוֹם אַחֵר. אֲבָל אֵינוֹ צָרִיךְ לִהְיוֹת מַתְנֶה עַל אַחֵר חוּץ מִבְּנוֹ וַאֲפִלּוּ הָיָה עִמּוֹ בְּמִשְׁתֶּה. לְפִיכָךְ בֶּן חָבֵר שֶׁהָיָה מֵסֵב בְּמִשְׁתֶּה עַם הָאָרֶץ אֵין הַסְּעֻדָּה בְּחֶזְקַת מְעֻשֶּׂרֶת שֶׁמָּא אָבִיו הִתְנָה עָלָיו:
כסף משנה
7.
Just as a person may eat with a common person and rely on the conditions in his heart, so too, he must make a stipulation with regard to what his son eats.19I.e., just as the previous halachah explains how the chavair must make stipulations for himself, so too, he must make stipulations for his son. [This applies] even if his son is in another place.20The son was eating together with a common person, but the father was not. He does not have to make a stipulation with regard to another person aside from his son even if that person was together with him at the feast.
Therefore if the son of a chavair is present at a feast with a common person, we cannot assume that the food was tithed, for perhaps [the chavair] made a stipulation for [the food] his son ate.21As the previous halachah stated with regard to his own self.

הלכה ח
עַם הָאָרֶץ שֶׁנָּתַן מָעָה לְחָבֵר וְאָמַר לוֹ קַח לִי אֲגֻדַּת יָרָק אַחַת אוֹ גְּלֻסְקָא אַחַת לוֹקֵחַ לוֹ סְתָם וּפָטוּר מִלְּעַשֵּׂר. וְאִם הֶחֱלִיף אֶת הַמָּעָה חַיָּב לְעַשֵּׂר וְאַחַר כָּךְ יָבִיא לוֹ. וְאִם פֵּרֵשׁ הֶחָבֵר וְלֹא לְקָחָן סְתָם אֶלָּא אָמַר לַחֶנְוָנִי אֲגֻדָּה זוֹ שֶׁאֲנִי לוֹקֵחַ מִמְּךָ לַחֲבֵרִי אֲנִי קוֹנֶה אוֹתָהּ וְזוֹ לְעַצְמִי אֲנִי קוֹנֶה אוֹתָהּ. זוֹ שֶׁלָּקַח לְעַצְמוֹ חַיָּב לְעַשְּׂרָהּ. וְזוֹ שֶׁלָּקַח לַחֲבֵרוֹ אֵינוֹ צָרִיךְ לְעַשְּׂרָהּ. וְאִם נִתְעָרְבוּ אֲפִלּוּ נִתְעָרְבָה אַחַת שֶׁלּוֹ בְּמֵאָה שֶׁל חֲבֵרוֹ מְתַקֵּן הַכּל דְּמַאי. וְאַחַר כָּךְ יִתֵּן לַחֲבֵרוֹ שֶׁשְּׁלָחוֹ לִקַּח לוֹ:
כסף משנה
8.
When a common person gives a meah22A silver coin of little value employed in the Talmudic era. to a chavair and tells him: "Buy me a bunch of vegetables or a cake," he may purchase it for him without any qualification and is not obligated to tithe it.23I.e., as stated in Halachah 1, a chavair must tithe what he buys and sells. Nevertheless, in this instance, he is not considered as buying or selling, but merely as acting as an agent for the common person.
In his Commentary to the Mishnah (Demai 6:12), the Rambam elaborates in his description of this situation, explaining that we are speaking about a situation where the seller of the produce is also a chavair and knows that the other chavair has been sent by the common person to purchase produce. If the chavair who is the agent asks to purchase produce without qualifying his statements and explaining who he is purchasing it for, the seller must give him tithed produce. For he knows that the agent is purchasing for the common person and he does not want to cause the common person to sin.
If [the agent] exchanged the meah, he is obligated to tithe [the produce he purchased].24If the seller sees that the agent uses his own money, he might suspect that he is purchasing the produce for himself and not for the common person. Hence, the seller might not tithe the produce (Kessef Mishneh).
If the chavair was explicit and did not buy the produce without explanation, but instead said: "This bunch of produce that I am purchasing from you is being bought for my colleague and this bunch is being bought for myself," he is obligated to tithe [only] the produce that he took for himself. He does not have to tithe [the bunch he purchased for his colleague].25The seller will not give him untithed produce for the common person, because he fears that he will partake of it without tithing it. He may, however, give the chavair untithed produce, for he knows that the chavair will not partake of it without tithing it (the Rambam's Commentary to the Mishnah loc. cit.). If these [two batches of produce] became intermingled, even if one measure [belonging to the chavair] becomes mixed with 100 [belonging to the common person], he must make the separations as if the entire quantity was demai.26We do not apply the principle of bereirah and say that the produce that the agent takes as his own was in fact the produce from which he separated the tithes.
All the above applies if the purchaser does not ask the seller if the produce was tithed. If, however, he asks the seller and the seller states that the produce was tithed, the agent does not have to make any separations, since the seller is also trustworthy (ibid.). Kin'at Eliyahu questions the very basis of the Rambam's assumption. For if the seller is a chavair, he would always tithe his produce and there would be no obligation to tithe produce purchased from him. See also the Radbaz who understands the halachah as speaking about a seller who is a common person.
[Only] afterwards27I.e., after he separated the tithes. may he give the produce to the colleague who sent him to purchase them for him.

הלכה ט
חֲמִשָּׁה שֶׁאָמְרוּ לְאֶחָד צֵא וְהָבֵא לָנוּ חָמֵשׁ אֲגֻדּוֹת שֶׁל יָרָק. וְהֵבִיא לְכָל אֶחָד וְאֶחָד בִּפְנֵי עַצְמוֹ. חֲבֵרִים שֶׁבָּהֶן אֵין צְרִיכִין לְעַשֵּׂר אֶלָּא עַל חֶלְקָן בִּלְבַד. הֵבִיא לָהֶן בְּעִרְבּוּב חֲבֵרִים שֶׁבָּהֶם צְרִיכִין לְעַשֵּׂר הַכּל:
כסף משנה
9.
When five people tell one person: "Bring us five bunches of vegetables," and [the agent] brings each person one bunch individually, the chavairim among [the recipients] are required to tithe only their portions.28We do not require them to separate tithes for the entire amount. They are not responsible for the portion of the other individuals. If [the agent] brought [the entire quantity] mixed together, the chavairim among [the recipients] are required to separate tithes for the entire amount.29Since the portion belonging to the common person is not distinct, we do not apply the principle of bereirah (Radbaz). Thus when making the division, it is as if each person is selling to the other (Kessef Mishneh). Alternatively, the agent indeed purchased the produce for all five individuals and then the entire mixture became intermingled (Rav Yosef Korcus).

הלכה י
עַם הָאָרֶץ שֶׁאָמַר לְחָבֵר צֵא וְלַקֵּט לִי תְּאֵנִים מִתְּאֵנָתִי אוֹכֵל מֵהֶן הֶחָבֵר עַרְאַי וּמְעַשְּׂרָן [דְּמַאי]. וְאִם אָמַר הֶחָבֵר לְעַם הָאָרֶץ לִלְקֹט לוֹ וְשָׁמַע חָבֵר אַחֵר זֶה הָאַחֵר אוֹכֵל וְאֵינוֹ צָרִיךְ לְעַשֵּׂר שֶׁאֵין הֶחָבֵר מוֹצִיא דָּבָר שֶׁאֵינוֹ מְתֻקָּן מִתַּחַת יָדוֹ וְחֶזְקָתוֹ שֶׁהִפְרִישׁ עָלֶיהָ מִמָּקוֹם אַחֵר. אַף עַל פִּי שֶׁלֹּא נֶחְשְׁדוּ חֲבֵרִים לִתְרֹם שֶׁלֹּא מִן הַמֻּקָּף, כְּדֵי לְסַלֵּק הַמִּכְשׁוֹל מִלִּפְנֵי עַם הָאָרֶץ תּוֹרְמִין:
כסף משנה
10.
When a common person tells a chavair: "Collect figs for me from my fig tree," the chavair may snack from them30Without tithing. Since a present is not like a sale (Chapter 5, Halachah 6), he is not considered to have purchased the figs from the common person. That would have required him to tithe (Radbaz). and tithe them as one tithes demai.31If he desires to eat a significant meal of them. He cannot be certain that the produce is untithed, because it is possible that the common person separated the tithes from other produce (ibid.). The Kessef Mishneh, by contrast, explains that there is an error in the text and he is in fact making separations from produce that is definitely untithed.
If a chavair told a common person to gather figs for him and another chavair heard him, the latter may partake [of the figs] without tithing them. [The rationale is that] a chavair will not release produce from his domain unless the appropriate separations were made. [Thus] we can assume that [the owner] separated [terumah and the tithes for this produce] from other [produce]. Although [generally] we do not suspect that a chavair will separate terumah from produce that is not in the same place as the terumah,32See Hilchot Terumah 3:17 with regard to the great terumah, ibid.:20 with regard to terumat ma'aser. he may do so to prevent the common person from confronting a spiritual stumbling block.33For we fear that the common person will partake of the produce without separating the tithes and thus without separating terumat ma'aser. We do not, however, fear that the common person will partake of produce without separating the great terumah.

הלכה יא
מֻתָּר לְהַאֲכִיל אֶת הָעֲנִיִּים וְאֶת הָאוֹרְחִים דְּמַאי וְצָרִיךְ לְהוֹדִיעָן. וְהֶעָנִי עַצְמוֹ וְהָאוֹרֵחַ אִם רָצוּ לְתַקֵּן מְתַקְּנִין:
כסף משנה
11.
It is permitted to feed34In his Commentary to the Mishnah (Demai 3:1), the Rambam explains that this wording implies that the poor are given only one meal's worth of food. If they are given a substantial amount, they must make the appropriate separations. Support for this leniency can be derived from the fact that the majority of the common people do in fact separate the tithes. demai to the poor and to guests.35Without separating tithes from it. This is a leniency instituted so that people will give charity and show hospitality (ibid.).
Although guests may themselves be wealthy, since they are required to accept hospitality, they are considered as poor (Meiri, Eruvin 31a).
They must, however, be notified of such. If the poor person or the guest desire to make the appropriate separations, they should.

הלכה יב
גַּבָּאֵי צְדָקָה גּוֹבִין סְתָם מִכָּל אָדָם וּמְחַלְּקִים סְתָם וְהָרוֹצֶה לְתַקֵּן יְתַקֵּן:
כסף משנה
12.
The collectors of charity collect from all people36I.e., even common people. without clarifying [whether separations have been made] and they divide the donations without specifications. If one desires to make the appropriate separations, he should.

הלכה יג
רוֹפֵא חָבֵר שֶׁהָיָה מַאֲכִיל לְחוֹלֵה עַם הָאָרֶץ מִפֵּרוֹת עַם הָאָרֶץ נוֹתֵן לְתוֹךְ יָדוֹ אֲבָל לֹא לְתוֹךְ פִּיו. וְאִם הָיָה הַדְּמַאי שֶׁל רוֹפֵא אֲפִלּוּ לְתוֹךְ יָדוֹ לֹא יִתֵּן. וְכֵן אִם יָדַע שֶׁהוּא טֶבֶל וַדַּאי אֲפִלּוּ לְתוֹךְ יָדוֹ אָסוּר:
כסף משנה
13.
When a doctor who is a chavair is feeding a common person who is sick37But not in mortal danger. Needless to say, if the sick person is in mortal danger, any prohibition can be violated to save his life. A person who is not dangerously ill is generally not permitted to partake of any substance that is forbidden by Rabbinic decree (Shulchan Aruch, Yoreh De'ah 155:3). Nevertheless, since the prohibition against demai is more of a safeguard than an outright ban, leniency was granted. from the produce of a common person, he should place [the food] in his hand, but not in his mouth.38So that he will not be directly responsible for feeding him demai. If the demai belonged to the doctor, he should not even place it in his hand. And similarly, if he knows that it is definitely tevel,39Even if it belongs to the common person. it is forbidden to place it in his hand.

זרעים הלכות מעשרות פרק י
Zeraim Maaser Chapter 10