נשים
הלכות יבום וחליצה
פרק א
Nashim
Yibum and Chalitzah
Chapter 1

Halacha

הלכה א
מִצְוַת עֲשֵׂה מִן הַתּוֹרָה שֶׁיְּיַבֵּם אָדָם אֵשֶׁת אָחִיו מֵאָבִיו בֵּין מִן הַנִּשּׂוּאִין בֵּין מִן הָאֵרוּסִין אִם מֵת בְּלֹא זֶרַע שֶׁנֶּאֱמַר (דברים כה ה) ״וּבֵן אֵין לוֹ״‎‎ (דברים כה ה) ״יְבָמָהּ יָבֹא עָלֶיהָ״‎‎. וּמִן הַתּוֹרָה אֵין צָרִיךְ לְקַדֵּשׁ יְבִמְתּוֹ שֶׁזּוֹ אִשְׁתּוֹ הִיא שֶׁהִקְנוּ אוֹתָהּ לוֹ מִן הַשָּׁמַיִם אֶלָּא יָבוֹא עָלֶיהָ. וּכְתֻבָּתָהּ עַל נִכְסֵי בַּעְלָהּ שֶׁמֵּת:
כסף משנה
1.
It is a positive commandment1Sefer HaMitzvot (Positive Commandment 216) and Sefer HaChinuch (Mitzvah 598) include this mitzvah as one of the 613 mitzvot of the Torah.
In his Guide for the Perplexed, the Rambam explains that marriage of this nature was a custom carried out before the giving of the Torah (as reflected by Genesis 38:8 , and the Torah allowed this rite to be perpetuated. Sefer HaChinuch explains that the closeness shared with the deceased by both his widow and his brother enjoins them to come together and produce a child who will perpetuate the deceased's memory and virtue. As Sefer HaChinuch mentions, there are also profound mystic concepts associated with this mitzvah.
of Scriptural law for a man to marry the widow of his paternal2Implied is an exclusion. One should not perform this rite with the widow of one's maternal brother (Yevamot 17b; Halachah 7 below). brother if he died without leaving children, as [Deuteronomy 25:5] states: "[And one of them dies] childless,... her husband's brother should cohabit with her." [This applies to a widow] from nisu'in, or from erusin.
[The childless widow is referred to as a yevamah; the rite through which they marry, yibbum.]
Scriptural law does not require a man to consecrate his yevamah, for she is his wife that heaven acquired for him. [All that is necessary] is that he cohabit with her. Her deceased husband's estate is responsible for her marriage contract.3See Hilchot Ishut 22:10-14.

הלכה ב
לֹא רָצָה לְיַבֵּם אוֹ שֶׁלֹּא רָצְתָה הִיא. הֲרֵי זֶה חוֹלֵץ לָהּ וְאַחַר כָּךְ תִּהְיֶה מֻתֶּרֶת לְהִנָּשֵׂא לְאַחֵר. וּמִצְוַת עֲשֵׂה מִן הַתּוֹרָה לַחֲלֹץ אִם לֹא רָצָה לְיַבֵּם שֶׁנֶּאֱמַר (דברים כה ט) ״וְחָלְצָה נַעֲלוֹ״‎‎ וְגוֹ'. וּמִצְוַת יִבּוּם קוֹדֶמֶת לְמִצְוַת חֲלִיצָה:
כסף משנה
2.
If the yavam does not want to perform the rite of yibbum, or if the woman does not consent,4According to the Rambam's conception, the woman cannot be compelled to marry her brother-in-law against her will. See Chapter 2, Halachah 10 and notes. he should [free her from this obligation through the rite of] chalitzah. [Only] afterwards is she permitted to marry another man.
It is a positive commandment5Sefer HaMitzvot (Positive Commandment 217) and Sefer HaChinuch (Mitzvah 599) include this mitzvah as one of the 613 mitzvot of the Torah. of Scriptural law for [a brother] to perform chalitzah for [the deceased's widow], if he does not want to perform the rite of yibbum, as [Deuteronomy 25:9] states: "She shall... remove his shoe."6The woman also participates - indeed she plays a more active role - in the rite of chalitzah. Nevertheless, the mitzvah is considered to be incumbent on the brother of the deceased, because the effect of this mitzvah is that he foregoes a right - the right to marry the woman - that belongs to him. Until he performs chalitzah, the woman is bonded to him, and through performing chalitzah he severs this connection. Therefore, the mitzvah is considered his.
Moreover, chalitzah is a means to dissolve the connection established by kiddushin. Since kiddushin are established by the man, chalitzah is also his initiative. See the Kovetz who questions whether the man is obligated to perform chalitzah or he merely has the opportunity of doing so.

The mitzvah of yibbum takes precedence over the mitzvah of chalitzah.7The concluding mishnah of the first chapter of Bechorot states:

The mitzvah of yibbum takes precedence over the mitzvah of chalitzah. [This applied] originally, when the participants [in the rite] intended to perform a mitzvah. In the present age, when they do not intend to perform a mitzvah, the mitzvah of chalitzah takes precedence over the mitzvah of yibbum.

In his Commentary on the Mishnah, the Rambam explains that the Mishnah follows the opinion of Abba Shaul, who maintains that the prohibition against marrying one's brother's wife is not removed entirely by the mitzvah of yibbum. Instead, it is merely temporarily superseded. And therefore, if the couple have any intentions other than the fulfillment of the mitzvah, they transgress this prohibition. As such, rather than involve oneself in such a challenge, one should perform the mitzvah of chalitzah.
In that commentary, and in a subsequent responsum, the Rambam explains that the halachah follows the opinion of the Sages who differ with Abba Shaul. These Sages maintain that when a man dies childless, the prohibition against his brother's marrying his wife is lifted entirely. Even if the brother marries the widow because of her looks, or because of her money, there is no prohibition involved. For that reason, the mitzvah of yibbum takes precedence.
The Ashkenazic community, following the rulings of Rabbenu Tam and the authorities who succeeded him, do not accept this ruling and follow Abba Shaul's opinion. Accordingly, the Shulchan Aruch (Even HaEzer 165:1) quotes the Rambam's view, while the Ramah states that chalitzah is preferable, and that a couple should not be allowed to perform yibbum unless the court is certain that their intent is solely to perform the mitzvah.
There is some discussion of the Rambam's intent by the commentaries, for his ruling in Hilchot Gerushin 10:16 implies a recognition of the importance of chalitzah. Nevertheless, the clarity of his statements in his Commentary on the Mishnah and in Sefer HaMitzvot makes it obvious that he follows the opinion of the Sages who differ with Abba Shaul. At present, even within the Sephardic community, the mitzvah of chalitzah is generally observed.
[Note also the opinion of the Beit Shmuel 174:3, who states that even according to the Ashkenazic authorities, by Scriptural law yibbum takes precedence, and that the primacy given to chalitzah is a Rabbinic institution.]

הלכה ג
זֶה שֶׁנֶּאֱמַר בַּתּוֹרָה (דברים כה ה) ״וּבֵן אֵין לוֹ״‎‎ אֶחָד הַבֵּן וְאֶחָד הַבַּת אוֹ זֶרַע הַבֵּן אוֹ זֶרַע הַבַּת הוֹאִיל וְיֵשׁ לוֹ זֶרַע מִכָּל מָקוֹם. וּבֵין מֵאִשָּׁה זוֹ בֵּין מֵאַחֶרֶת הֲרֵי זֶה פּוֹטֵר אֶת אִשְׁתּוֹ מִן הַחֲלִיצָה וּמִן הַיִּבּוּם. אֲפִלּוּ הָיָה לוֹ זֶרַע מַמְזֵר אוֹ עוֹבֵד עֲבוֹדָה זָרָה הֲרֵי זֶה פּוֹטֵר אֶת אִשְׁתּוֹ מִן הַחֲלִיצָה וּמִן הַיִּבּוּם:
כסף משנה
3.
The Torah's words [Deuteronomy 25:5], "When one of them dies childless" [should not be interpreted narrowly].8The Hebrew word בן, translated as "son," can also mean "child" or "descendant." Hence, the ruling mentioned by the Rambam. [When the deceased] has a son, a daughter, a descendant of a son, or a descendant of a daughter, as long as he has left progeny9If, however, a man fathered a child [or children], and he [they all] died in the father's lifetime, the man's wife is obligated to perform the rite of yibbum. - whether from the woman [to whom he is presently married] or from another woman, his wife is free from the obligation of chalitzah or yibbum.
Even if he has a descendant who is illegitimate or an idolater, [that descendant] frees [the deceased's] wife from the obligation of chalitzah or yibbum.

הלכה ד
אֲבָל בְּנוֹ מִן הַשִּׁפְחָה וּמִן הַכּוּתִית אֵינוֹ פּוֹטֵר אֶת אִשְׁתּוֹ שֶׁזֶּרַע הַבָּא מִן הַשִּׁפְחָה עֲבָדִים וְהַבָּא מִן כּוּתִית כּוּתִי וּכְאִלּוּ אֵינָם. הֲרֵי הוּא אוֹמֵר בְּשִׁפְחָה (שמות כא ד) ״הָאִשָּׁה וִילָדֶיהָ תִּהְיֶה לַאדֹנֶיהָ״‎‎ מְלַמֵּד שֶׁוְּלָדָהּ כְּמוֹתָהּ. וּבְכוּתִית הוּא אוֹמֵר (דברים ז ד) ״כִּי יָסִיר אֶת בִּנְךָ מֵאַחֲרַי״‎‎ מֵסִיר אוֹתוֹ מִלֵּחָשֵׁב בַּקָּהָל. וְאַף עַל פִּי שֶׁנִּשְׁתַּחְרֵר בְּנוֹ מִן הַשִּׁפְחָה אוֹ נִתְגַּיֵּר בְּנוֹ מִן הַכּוּתִית הֲרֵי הֵן כִּשְׁאָר הַגֵּרִים וְהַמְשֻׁחְרָרִין וְאֵינָם פּוֹטְרִין אֶת אִשְׁתּוֹ. הֲרֵי שֶׁהָיָה לוֹ בֵּן מִן הַשִּׁפְחָה שֶׁלּוֹ וְשִׁחְרְרוֹ וְשִׁחְרְרָהּ וּנְשָׂאָהּ וּמֵת בְּלֹא זֶרַע הֲרֵי זוֹ תִּתְיַבֵּם לְאָחִיו וְאַף עַל פִּי שֶׁבְּנָהּ מִמֶּנּוּ קַיָּם שֶׁכְּבָר שִׁחְרְרוֹ:
כסף משנה
4.
[The above applies to children born from a Jewish woman.] If, however, [a deceased man] has a child born from a maidservant or a gentile woman, his wife is not free of these obligations. For the offspring of a maidservant are servants. And the offspring of a gentile woman are gentiles, and considered as if they have no connection to him.
[These concepts are derived as follows:] With regard to a maidservant, [Exodus 21:4] states: "The woman and her children will belong to her master," teaching that her offspring have the same status as she.10Regardless of who the father is. And with regard to a gentile woman, [Deuteronomy 7:4] states: "They will lead your son away from Me" - i.e., prevent him from being considered part of the congregation.
Even when a man's son born from a maidservant is freed, or his son born from a gentile woman converts, he is regarded in the same way as other converts or freed slaves and does not cause [the deceased's] wife to be freed [from the obligation of yibbum]. [Even when a man] fathered a son with a maidservant, freed the son and the mother, and married her - if he dies without fathering any other children, his wife should perform the rite of yibbum with his brother, although the son [whom the deceased] fathered is alive and has been freed.11See Hilchot Gerushin 10:19.

הלכה ה
מִי שֶׁמֵּת וְהִנִּיחַ אִשְׁתּוֹ מְעֻבֶּרֶת. אִם הִפִּילָה אַחַר מוֹתוֹ הֲרֵי זוֹ תִּתְיַבֵּם. וְאִם יָלְדָה וְיָצָא הַוָּלָד חַי לַאֲוִיר הָעוֹלָם אֲפִלּוּ מֵת בְּשָׁעָה שֶׁנּוֹלַד הֲרֵי אִמּוֹ פְּטוּרָה מִן הַחֲלִיצָה וּמִן הַיִּבּוּם. אֲבָל מִדִּבְרֵי סוֹפְרִים עַד שֶׁיִּוָּדַע בְּוַדַּאי שֶׁכָּלוּ לוֹ חֳדָשָׁיו וְנוֹלַד לְתִשְׁעָה חֳדָשִׁים גְּמוּרִים. אֲבָל אִם לֹא נוֹדַע לְכַמָּה נוֹלַד. אִם חַי שְׁלֹשִׁים יוֹם הֲרֵי זֶה וְלַד קַיָּמָא וּפוֹטֵר נְשֵׁי אָבִיו מִן הַחֲלִיצָה וּמִן הַיִּבּוּם. וְאִם מֵת בְּתוֹךְ הַשְּׁלֹשִׁים אֲפִלּוּ בְּיוֹם הַשְּׁלֹשִׁים בֵּין שֶׁמֵּת מֵחלִי בֵּין שֶׁנָּפַל מִן הַגַּג אוֹ אֲכָלוֹ אֲרִי הֲרֵי זֶה סָפֵק נֵפֶל סָפֵק בֶּן קַיָּמָא וּצְרִיכָה חֲלִיצָה מִדִּבְרֵי סוֹפְרִים. אֲבָל לֹא תִּתְיַבֵּם:
כסף משנה
5.
[The following rules apply when a man] dies and leaves his wife pregnant: If she miscarries after he dies, his wife [is obligated to] perform the rite of yibbum. If she bore the child, and the fetus emerged into the world alive, the mother is free of the obligation to perform the rite of chalitzah or yibbum. This applies even when the child dies immediately after being born.
According to Rabbinic decree, however, [this does not apply] unless it is known that the child was carried for a full term pregnancy and was born after nine full months had passed.12The Ramah (Even HaEzer 156:4) states that these laws apply as long as we know that the pregnancy lasted into the ninth month. If, however, the term of the pregnancy is unknown [the following rules apply]: If the child lives 30 days, the child is considered viable, and he frees his father's wives from the obligation of yibbum or chalitzah.
If the child dies within 30 days [of his birth], even on the thirtieth day, there is a doubt whether the child is viable or non-viable. This applies regardless of [the cause of the infant's death], whether he died as a result of illness, fell from a roof or was eaten by a lion. According to Rabbinic law, [the deceased's wives] must perform the rite of chalitzah;13The Ramah (ibid.) rules that even if a fetus is stillborn, these laws still apply. they may not perform the rite of yibbum.14For according to Scriptural law, there is no obligation for yibbum, and the prohibition against relations with her husband's brother remains in force.

הלכה ו
מִי שֶׁיֵּשׁ לוֹ אָח מִכָּל מָקוֹם אֲפִלּוּ מַמְזֵר אוֹ עוֹבֵד עֲבוֹדָה זָרָה בֵּין קָטָן בֵּין גָּדוֹל מִשֶּׁיָּצָא רֹאשׁוֹ וְרֻבּוֹ לַאֲוִיר הָעוֹלָם קֹדֶם שֶׁיָּמוּת אָחִיו הֲרֵי זֶה זוֹקֵק אֶת אִשְׁתּוֹ לְיִבּוּם. וְאִם הָיָה לוֹ אָח מִן הַשִּׁפְחָה אוֹ מִן הַכּוּתִית אֵינוֹ אָחִיו לְדָבָר מִן הַדְּבָרִים וְאֵינוֹ זוֹקֵק אֶת אִשְׁתּוֹ. וְאַף עַל פִּי שֶׁהָיְתָה לֵדָתוֹ בִּקְדֻשָּׁה הוֹאִיל וְהָיְתָה הוֹרָתוֹ שֶׁלֹּא בִּקְדֻשָּׁה אֵינוֹ אָחִיו:
כסף משנה
6.
Whenever a man has a brother, even if the brother is illegitimate or an idolater, whether he is above the age of majority or below the age of majority,15In such an instance, the brother may not perform the rites of yibbum or chalitzah until he comes of age, as is explained below. as long as his head and the majority [of his body]16The Gur Aryeh notes that Hilchot Issurei Bi'ah 10:6 appears to imply that the emergence of an infant's forehead alone is sufficient for it to be considered having been "born." Hence, he interprets the Rambam's words as meaning either the forehead or the majority of the body. emerged into the world before his brother's death,17If, however, the brother is not born until after the man's death, the deceased's wife is not obligated to perform the rite of yibbum, as explained in Chapter 6, Halachah 16. his existence causes [his brother's wife] to be obligated to perform the rite of yibbum.18Needless to say, the woman should not marry the illegitimate man or the idolater. Instead, she should seek to be freed from her obligation through chalitzah.
The Shulchan Aruch (Even HaEzer 157:4) and the Ramah mention the possibility of leniency, if the deceased's brother was an apostate at the time the deceased married his wife.

If [the deceased] had a brother who was born to a maidservant or to a gentile woman, he is not considered to be his brother in any [halachic] context. [His existence] does not cause [his brother's wife] to be obligated to perform the rite of yibbum. Even when [the brother] was born as a member of the Jewish people,19I.e., the maidservant was freed, or the gentile woman was converted, before the baby was born. since his mother was not Jewish when he was conceived, he is not considered to be [the deceased's] brother.

הלכה ז
אַחִים מִן הָאֵם אֵינָן חֲשׁוּבִין אַחִים (אֶלָּא לַאֲבֵלוּת וּלְעֵדוּת אֲבָל) לְעִנְיַן יְרֻשָּׁה אוֹ לְעִנְיַן יִבּוּם וַחֲלִיצָה הֲרֵי הֵן כְּמִי שֶׁאֵינָן. שֶׁאֵין אַחְוָה אֶלָּא מֵאָב:
כסף משנה
7.
Maternal brothers are considered to be brothers only with regard to the laws of mourning20See Hilchot Aveilut 2:1. and the laws of witnesses.21See Hilchot Edut 13:1.
With regard to the laws of inheritance,22See Hilchot Nachalot 1:6. and the laws of yibbum and chalitzah, [maternal brothers] are considered as if they did not exist. For fraternity is derived from the father alone.23Yevamot 17b derives this concept from Genesis 42:13: "We are twelve brothers, the son of one father."

הלכה ח
גֵּרִים שֶׁנִּתְגַיְּרוּ וַעֲבָדִים שֶׁנִּשְׁתַּחְרְרוּ אֵין לָהֶן אַחְוָה כְּלָל וַהֲרֵי הֵן כְּזָרִים זֶה לָזֶה. וַאֲפִלּוּ אֶחָד מֵהֶם הוֹרָתוֹ שֶׁלֹּא בִּקְדֻשָּׁה וְלֵדָתוֹ בִּקְדֻשָּׁה וְהַשֵּׁנִי הוֹרָתוֹ וְלֵדָתוֹ בִּקְדֻשָּׁה הֲרֵי הֵן כְּזָרִים. וַאֲפִלּוּ תְּאוֹמִים וְנוֹלְדוּ בִּקְדֻשָּׁה אֵין בֵּינֵיהֶן אַחְוָה עַד שֶׁתְּהֵא הוֹרָתָן וְלֵדָתָן בִּקְדֻשָּׁה:
כסף משנה
8.
There is no concept of fraternity among converts and freed slaves. [Thus, even two converts or two freed slaves born from the same father] are considered unrelated.24And therefore, one is not obligated to perform the rite of yibbum if his brother dies childless. Even if one of them was conceived before his parents were converted and born after they were converted, and the other was conceived and born after the parents were converted, they are not considered to have any family connection.
Even if they are twins who were born after their parents were converted, they are not considered to be brothers25This ruling applies with regard to the laws of yibbum. With regard to the laws of forbidden relationships, by contrast, in Hilchot Issurei Bi'ah the Rambam rules that if one twin has relations with the other's wife, he is liable for transgressing the prohibition against relations with his brother's wife. unless they were also conceived after their parents converted.

הלכה ט
מִי שֶׁהָיוּ לוֹ נָשִׁים רַבּוֹת וָמֵת. בִּיאָתָהּ אוֹ חֲלִיצָתָהּ שֶׁל אַחַת מֵהֶן פּוֹטֶרֶת אֶת הַשְּׁאָר וְאֵינוֹ מְיַבֵּם לִשְׁתַּיִם שֶׁנֶּאֱמַר (דברים כה ט) ״אֲשֶׁר לֹא יִבְנֶה אֶת בֵּית אָחִיו״‎‎ בַּיִת אֶחָד הוּא בּוֹנֶה וְאֵינוֹ בּוֹנֶה שְׁנֵי בָּתִּים. וְכֵן אִם הָיוּ לוֹ אַחִים רַבִּים אֶחָד מֵהֶן חוֹלֵץ אוֹ מְיַבֵּם לְאַחַת מִן הַיְבָמוֹת וְיֻתְּרוּ שְׁאָר הַצָּרוֹת:
כסף משנה
9.
When a man who has many wives dies, [a brother who] engages in relations or performes the rite of chalitzah with one of them frees the others from all obligations. [The deceased's brother] may not marry two [of the deceased's wives], as [implied by Deuteronomy 25:9]: "...who did not build his brother's house." [This is interpreted as an exclusion:] he may build one house, but not two houses.26As reflected in Halachah 12, there is a prohibition involved.
Similarly, if [the deceased had many brothers, one of them should perform either the rite of chalitzah or yibbum with one of the widows. This frees the others of all obligations.

הלכה י
הָיוּ בִּיבָמוֹת אֵלּוּ כְּשֵׁרוֹת לִכְהֻנָּה וּפְסוּלוֹת. אִם הָיָה מְיַבֵּם מְיַבֵּם לְאֵי זוֹ שֶׁיִּרְצֶה. וְאִם הָיָה חוֹלֵץ יַחֲלֹץ לַפְּסוּלָה כְּדֵי שֶׁלֹּא יִפְסל אֶת הַכְּשֵׁרָה לִכְהֻנָּה בַּחֲלִיצָה:
כסף משנה
10.
[The following rules apply if] the widows include some who are fit to marry into the priesthood, and some who are not fit to marry into the priesthood: If [the brother] desires to perform the rite of yibbum, he may choose any of the widows that he desires. If he desires to perform the rite of chalitzah, he should perform this rite with one of the wives who is already forbidden to the priesthood, so that he will not disqualify one of the women who may marry into the priesthood through the rite of chalitzah.27Our Sages forbade a priest from marrying a woman who performed the rite of chalitzah (Hilchot Ishut 1:7). Since it makes no difference to the brother with which widow he performs the rite of chalitzah, our Sages counsel that it be performed in a manner that does not damage a woman's future possibilities. See Yevamot 44a.
A court should enforce the application of this law (Beit Shmuel 161:2).

הלכה יא
מֵתוּ לוֹ אַחִין רַבִּים וְנָפְלוּ נְשׁוֹתֵיהֶן לְפָנָיו. אִם אֶפְשָׁר לוֹ לְיַבֵּם אֶת כֻּלָּן מְיַבֵּם וְאִם לָאו חוֹלֵץ. אוֹ חוֹלֵץ לְמִי שֶׁיִּרְצֶה מֵהֶן וּמְיַבֵּם לְמִי שֶׁיִּרְצֶה אַחַת מִכָּל בַּיִת וּבַיִת:
כסף משנה
11.
[The following rules apply if] many [of a man's] brothers die and he [becomes obligated to perform the rite of yibbum or chalitzah] to [all] their wives: If it is possible for him to perform the rite of yibbum with all of them,28I.e., if he is capable of meeting the responsibilities a husband has - providing for his wife's livelihood, her clothing and her conjugal rights. he should. If not, he may perform chalitzah with all of them, or perform chalitzah with whomever he desires, or perform yibbum with whomever he desires, [choosing one of the widows] from each [of his deceased brother's] households.

הלכה יב
הַכּוֹנֵס אֶת יְבִמְתּוֹ נֶאֶסְרוּ צָרוֹתֶיהָ עָלָיו וְעַל שְׁאָר הָאַחִין וְאִם בָּא הוּא אוֹ אֶחָד מֵהָאַחִין עַל צָרָתָהּ הֲרֵי זֶה עוֹבֵר בַּעֲשֵׂה שֶׁנֶּאֱמַר (דברים כה ה) ״יְבָמָהּ יָבֹא עָלֶיהָ״‎‎ וְלֹא עָלֶיהָ וְעַל צָרָתָהּ וְלָאו הַבָּא מִכְּלַל עֲשֵׂה עֲשֵׂה. וְכֵן הַחוֹלֵץ לִיבִמְתּוֹ נֶאֶסְרָה הַחֲלוּצָה הִיא וְכָל צָרוֹתֶיהָ עַל הַחוֹלֵץ וְעַל שְׁאָר אַחִין. וְכֻלָּן אֲסוּרוֹת עֲלֵיהֶן מִדִּבְרֵי סוֹפְרִים כִּשְׁנִיּוֹת. שֶׁמֵּאַחַר שֶׁמֵּת אָחִיו בְּלֹא וָלָד נִסְתַּלֵּק אִסּוּר עֶרְוָה מֵעַל כָּל נָשָׁיו לְפִיכָךְ תּוֹפְסִין בָּהֶן הַקִּדּוּשִׁין כִּשְׁנִיּוֹת:
כסף משנה
12.
When [a yavam] marries a yevamah, all the other widows from that household become forbidden to him and to his other brothers. If he or his other brothers have relations with one of the other widows, they transgress a positive commandment, for [Deuteronomy 25:9] states: "Her yavam will engage in relations with her." [This is interpreted to mean:] With her, and not with another woman from that household. A prohibition stemming from a positive commandment is considered to be a positive commandment.29A person who transgresses a positive commandment is not liable to receive the forty lashes given when a negative commandment of the Torah is violated. Hence, the Rambam clarifies that although a prohibition is involved, it is a prohibition stemming from a positive commandment, and not one stemming from a negative commandment.
Similarly, when [one of the brothers] performs chalitzah with his yevamah, the woman with whom chalitzah was performed and all the other widows from that household become forbidden to [the brother who] performed chalitzah and to the other brothers. They are all forbidden to the brothers by Rabbinic decree,30The Ramban (Nachmonides, Hasagot L'Sefer HaMitzvot, Hosafot Negative Commandment 14) differs and maintains that the violation of a Scriptural prohibition is involved. The difference between their opinions stems from their interpretation of Yevamot 10b.
That passage interprets Deuteronomy 25:9: "... who did not build his brother's house," as implying a prohibition. "Once he did not build it, he no longer has the right to build it." The Ramban follows the authorities who maintain that this is a Scriptural prohibition, while the Rambam (based on Yevamot 40b) maintains that the prohibition is Rabbinic in origin, and the reference to the verse is merely an asmachta, a support.
sharing the status of sh'niyot.31Literally, "prohibitions of a second degree," relatives with whom relations are permitted by Scriptural law, but forbidden by Rabbinic decree. See Hilchot Ishut 1:6. [This is the only prohibition involved,] for since their brother died childless, the severe prohibition against sexual relations (issur ervah) is removed. Therefore, [if one of the brothers consecrates such a woman,] the consecration is binding, as it would be if he consecrated one of the sh'niyot.

הלכה יג
הַחוֹלֵץ לִיבִמְתּוֹ כְּשֵׁם שֶׁהִיא אֲסוּרָה עָלָיו כָּךְ קְרוֹבוֹתֶיהָ אֲסוּרוֹת עָלָיו. כְּגוֹן אִמָּהּ וּבִתָּהּ. וְכֵן הִיא אֲסוּרָה לִבְנוֹ וּלְאֶחָיו. וַאֲפִלּוּ שְׁנִיּוֹת שֶׁלָּהּ אֲסוּרוֹת כְּגוֹן בַּת בַּת בִּתָּהּ. וְכֵן הִיא אֲסוּרָה לְבֶן בֶּן בְּנוֹ. כְּלָלוֹ שֶׁל דָּבָר הֲרֵי הִיא כְּאִשְׁתּוֹ שֶׁגֵּרְשָׁהּ. וְכֵן אִם מֵתָה יְבִמְתּוֹ וַעֲדַיִן הִיא זְקוּקָה לוֹ אָסוּר בִּקְרוֹבוֹתֶיהָ כְּאִלּוּ הָיְתָה אִשְׁתּוֹ וּמֵתָה תַּחְתָּיו. וְכָל הָאִסּוּרִין הָאֵלּוּ מִדִּבְרֵיהֶן. וּמֻתָּר אָדָם לִשָּׂא אֲחוֹת צָרַת חֲלוּצָתוֹ וּשְׁאָר קְרוֹבוֹתֶיהָ:
כסף משנה
13.
When a person performs the rite of chalitzah with his yevamah, not only does she become forbidden to him, but her relatives32This refers to seven women who are included in the category of arayot and with whom sexual relations are forbidden, as mentioned in Leviticus, Chapter 18, and Hilchot Issurei Bi'ah 2:7,9. They include her mother, both her maternal and paternal grandmothers, her daughter, the daughter of her son, the daughter of her daughter and her sister. - e.g., her mother and her daughter - also become forbidden. Similarly, she is forbidden to marry his son and his brother.33I.e., even a brother who was not born during the lifetime of the widow's husband. Even the sh'niyot - e.g., her daughter's granddaughter - related to her are forbidden to him, and she is forbidden to his son's grandson. To summarize: Her status is like that of a divorced wife.
Similarly, if his yevamah dies while she is still under obligation to him,34I.e., before she performs either yibbum or chalitzah. he is forbidden to marry these relatives of hers, as if she were his wife and she died in his lifetime.35He is, however, permitted to marry the woman's sister, just as he is allowed to marry his wife's sister after her death. All these prohibitions are of Rabbinic origin.
[If the deceased had two wives, his brother] may marry the sister of the wife with whom he did not perform the rite of chalitzah, or any other of her relatives.36Although the woman herself is forbidden, as stated in the previous halachah, her relatives are permitted.

הלכה יד
אָסוּר לְיָבָם לִשָּׂא קְרוֹבַת זְקוּקָתוֹ כְּגוֹן אִמָּהּ אוֹ בִּתָּהּ עַד שֶׁיְּיַבֵּם אֶחָד מֵאֶחָיו לָהּ אוֹ יַחֲלֹץ לָהּ וְתָסוּר זִקָּתוֹ מֵעָלֶיהָ וְיִשָּׂא אִמָּהּ אוֹ בִּתָּהּ אוֹ שְׁאָר קְרוֹבוֹתֶיהָ. אַף עַל פִּי שֶׁהֵן כֻּלָּן אֲסוּרוֹת עַל אָחִיו שֶׁחָלַץ אוֹ יִבֵּם כְּמוֹ שֶׁבֵּאַרְנוּ:
כסף משנה
14.
It is forbidden for a man to marry a close relative of a woman with whom he is obligated to perform either yibbum or chalitzah - e.g., her mother or her daughter - until one of his brothers performs yibbum with the woman who is obligated, or performs chalitzah with her to free her of her obligation.37See Chapter 7, Halachah 8.
Afterwards, [the other brother] may marry the woman's mother, daughter, or any of her other relatives, despite the fact that these relatives are all forbidden to the brother who performed either yibbum or chalitzah, as explained [in the previous halachah].

הלכה טו
הַכּוֹנֵס אֶת יְבִמְתּוֹ וְגֵרְשָׁהּ אִם רָצָה לְהַחֲזִיר יַחֲזִיר מִפְּנֵי שֶׁהִיא אִשְׁתּוֹ לְכָל דָּבָר וְלֹא נִשְׁאַר עָלֶיהָ שֵׁם אִסּוּר מִפְּנֵי אָחִיו כְּלָל לֹא מִדִּבְרֵי תּוֹרָה וְלֹא מִדִּבְרֵי סוֹפְרִים:
כסף משנה
15.
When a man marries his yevamah and then divorces her, he may remarry her if he so desires. She is considered to be his wife with regard to all matters. There remains no trace of the prohibition [that existed when she was] his brother's [wife], neither from Scriptural law nor from Rabbinic law.38I.e., we do not say that he has already fulfilled the mitzvah of yibbum, and now the woman's status reverts to the prohibition under which she was previously forbidden. See Yevamot 39a.

הלכה טז
כְּבָר בֵּאַרְנוּ בְּהִלְכוֹת אִישׁוּת שֶׁבֶּן תֵּשַׁע שָׁנִים וְיוֹם אֶחָד בִּיאָתוֹ בִּיאָה וְדָבָר זֶה הֲלָכָה מִפִּי הַקַּבָּלָה. לְפִיכָךְ יָבָם קָטָן שֶׁבָּא עַל יְבִמְתּוֹ אִם הָיָה בֶּן תֵּשַׁע שָׁנִים וְיוֹם אֶחָד יְקַיֵּם. אֲבָל אֵינוֹ חוֹלֵץ עַד שֶׁיִּגְדַּל וְיִבָּדֵק שֶׁהֲרֵי (דברים כה ז) ״אִישׁ״‎‎ כָּתוּב בַּפָּרָשָׁה לְעִנְיַן חֲלִיצָה. וְאִם הָיָה פָּחוֹת מִזֶּה אֵין בִּיאָתוֹ בִּיאָה. וּבִיאַת בֶּן תֵּשַׁע שָׁנִים אֵינָהּ קוֹנָה קִנְיָן גָּמוּר. לְפִיכָךְ אֵין יְבִמְתּוֹ נִתֶּרֶת לְזָר עַד שֶׁיָּבוֹא עָלֶיהָ אַחַר שֶׁיִּגְדַּל אוֹ עַד שֶׁתַּחֲלֹץ כְּמוֹ שֶׁיִּתְבָּאֵר:
כסף משנה
16.
As explained in Hilchot Ishut,39Chapter 11, Halachah 3. the sexual relations in which a boy of nine years and one day engages are halachically significant. This is a law received through the Oral Tradition.
Accordingly, when a yavam who is below the age of majority, but over the age of nine, engages in sexual relations with his yevamah, he should maintain [his bond with her].40I.e., none of the other brothers should marry her instead. See Chapter 5, Halachot 18-19. He may not, however, perform the rite of chalitzah until he attains the age of majority and is inspected [for signs of physical maturity].41Two pubic hairs, as stated in Hilchot Ishut 2:10. For with regard to chalitzah, the term ish ("man") is specifically mentioned in the Torah.42Deuteronomy 25:7 states: "If the man does not desire...."
If [a yavam] is below this age, sexual relations in which he engages are of no halachic significance. [Moreover,] even the sexual relations in which a nine-year-old engages do not acquire [the yevamah for him in a manner that is] binding [entirely].43Rather, these sexual relations are considered to be equivalent to a ma'amar, the status of which is discussed in Chapter 2, Halachah 1. Therefore, his yevamah is not permitted to marry another man until he engages in relations with her after he attains majority [and divorces her], or performs the rite of chalitzah [at that age], as will be explained.44See Chapter 5, Halachah 21, where this situation is described in detail.

הלכה יז
וְכֵן הַיְבָמָה הַקְּטַנָּה אִם רָצָה הַיָּבָם לְיַבֵּם אוֹתָהּ מְיַבֵּם אֲבָל אֵינָהּ חוֹלֶצֶת עַד שֶׁתַּגְדִּיל וְתִבָּדֵק. וַאֲפִלּוּ נִבְעֲלָה אַחַר י״‎ב שָׁנָה אֵינָהּ חוֹלֶצֶת עַד שֶׁתִּבְדֹּק וְיִמְצְאוּ בָּהּ הַסִּימָנִין:
כסף משנה
17.
Similarly, with regard to a yevamah who is below the age of majority: If her yavam desires to perform the rite of yibbum with her, he may.45Yevamot 119a explains that there is a certain dimension of leniency implied by this ruling. Since the woman is below the age of majority, it is possible that as she grows older she will manifest signs of being an aylonit, a woman who lacks female sexual characteristics (Hilchot Ishut 2:3,6). If that were to be the case, then the mitzvah of yibbum would not apply to such a woman, as stated in Chapter 6, Halachah 8, and relations with her would still be forbidden. Nevertheless, since the overwhelming probability is that a woman will not be an aylonit, our Sages did not impose any restrictions. He may not, however, perform the rite of chalitzah with her until she attains the age of majority and is inspected [for physical signs of maturity]. Even if she engaged in sexual relations after she became twelve years old,46Rav David Arameah interprets this to be referring to engaging in relations with her previous husband before her death. Although with regard to her husband, we assume that she has manifested signs of physical maturity, as stated in Hilchot Gerushin 11:5, with regard to the laws of yibbum and chalitzah an inspection is required. Note an alternative explanation offered by the Or Sameach. she may not perform the rite of chalitzah until she undergoes an inspection and manifests signs of physical maturity.

הלכה יח
כְּשֵׁם שֶׁאֵין הַיָּבָם חוֹלֵץ עַד שֶׁיֵּעָשֶׂה אִישׁ כָּךְ אֵין הַיְבָמָה חוֹלֶצֶת עַד שֶׁתֵּעָשֶׂה אִשָּׁה גְּדוֹלָה. וְיָבָם קָטָן שֶׁבָּא עַל יְבָמָה קְטַנָּה יִגְדְּלוּ זֶה עִם זֶה:
כסף משנה
18.
Just as a yavam may not perform chalitzah until he attains manhood, so too, a yevamah may not perform chalitzah until she attains womanhood.47See Chapter 6, Halachah 6.
When a yavam who is below the age of majority engages in sexual relations with a yevamah who is also below the age of majority, they should grow up together.

הלכה יט
הַיְבָמָה לֹא תִּתְיַבֵּם וְלֹא תַּחֲלֹץ עַד שֶׁתַּמְתִּין תִּשְׁעִים יוֹם חוּץ מִיּוֹם הַמִּיתָה וּמִיּוֹם הַיִּבּוּם וּמִיּוֹם הַחֲלִיצָה כִּשְׁאָר כָּל הַנָּשִׁים. וּמִפְּנֵי מָה לֹא תַּחֲלֹץ בְּתוֹךְ תִּשְׁעִים יוֹם מִפְּנֵי שֶׁאֵינָהּ רְאוּיָה לְיִבּוּם וְנֶאֱמַר (דברים כה ז) ״אִם לֹא יַחְפֹּץ הָאִישׁ לָקַחַת אֶת יְבִמְתּוֹ״‎‎ (דברים כה ט) ״וְחָלְצָה נַעֲלוֹ״‎‎ וְגוֹ' בְּעֵת שֶׁהִיא עוֹלָה לְיִבּוּם עוֹלָה לַחֲלִיצָה וְכָל זְמַן שֶׁאֵינָהּ עוֹלָה לְיִבּוּם אֵינָהּ עוֹלָה לַחֲלִיצָה. וְאִם יִבֵּם אוֹתָהּ אוֹ חָלַץ בְּתוֹךְ הַשְּׁלֹשָׁה חֳדָשִׁים הוֹאִיל וְאֵינָהּ מְעֻבֶּרֶת הֲרֵי זוֹ נִפְטְרָה וְאֵינָהּ צְרִיכָה כְּלוּם:
כסף משנה
19.
As all other women,48See Hilchot Gerushin 11:18, which prohibits a widow or a divorcee from remarrying within 90 days of her husband's death or their divorce, to preclude the possibility of questions arising concerning who is the father of her child. a yevamah should not perform either yibbum or chalitzah until she waits a 90-day interval. [These 90 days] do not include the day of her previous husband's death or the day of yibbum or chalitzah.
Why may she not perform chalitzah within these 90 days?49For performing chalitzah will not prevent the determination of a child's father. Because she is not fit to perform yibbum [at that time]. [Deuteronomy 25:7-9] states: "And if the man does not desire to take his yevamah,... she should remove his shoe" [establishing an equivalence between these two rites]. [Thus,] when she is fit to perform yibbum, she is fit to perform chalitzah. And when she is not fit to perform yibbum, she is not fit to perform chalitzah.50The converse of this principle - that one who does not perform chalitzah (e.g., a king) does not perform yibbum - also applies. See the Rambam's Commentary on the Mishnah, Sanhedrin 2:1 and Hilchot Melachim 2:3).
Should [a brother] perform yibbum or chalitzah with her within these three months, since she is not pregnant, she has discharged her obligation and need not perform any further activity.51The Ramah (Even HaEzer 164:1) differs and maintains that such a woman requires chalitzah from her deceased husband's other brothers after the three months have passed. See also Beit Shmuel 164:4.

הלכה כ
הַחוֹלֵץ לִיבִמְתּוֹ וְנִמְצֵאת מְעֻבֶּרֶת וְיָלְדָה. אִם הָיָה וָלָד שֶׁל קַיָּמָא הֲרֵי זוֹ כְּמִי שֶׁלֹּא נֶחְלְצָה לוֹ מֵעוֹלָם וּמֻתֶּרֶת לִכְהֻנָּה וּמֻתָּר בִּקְרוֹבוֹתֶיהָ. וְאִם הִפִּילָה אוֹ שֶׁלֹּא שָׁהָה שְׁלֹשִׁים יוֹם אַחַר שֶׁנּוֹלַד חוֹזֵר וְחוֹלֵץ לָהּ הוּא אוֹ אֶחָד מֵאֶחָיו. שֶׁחֲלִיצַת הַמְעֻבֶּרֶת אֵינָהּ חֲלִיצָה וּבִיאַת הַמְעֻבֶּרֶת אֵינָהּ יִבּוּם:
כסף משנה
20.
[The following rules apply when a brother] performs chalitzah with his yevamah, and afterwards it is discovered that she is pregnant: If she gives birth and the child is viable, it is considered as if she had never performed chalitzah. She is permitted to [marry into the] priesthood, and [the brother who performed chalitzah with her] is permitted [to marry] her relatives.
If the woman miscarries, or if the child who is born does not live for 30 days after being born, this - or another - brother52The Ramah (Even HaEzer 164:2) states that the chalitzah should be performed by another brother, and not by the brother who had originally performed chalitzah with her. should perform chalitzah with her again. For chalitzah performed with a pregnant woman is not considered chalitzah,53See Chapter 4, Halachah 26.
The Beit Shmuel 164:5 quotes the view of Tosafot, who maintain that, according to Rabbinic law, performing chalitzah while pregnant disqualifies a woman from marrying into the priesthood and prevents her from performing yibbum if she miscarries.
nor are relations with a pregnant woman considered yibbum.

הלכה כא
לְפִיכָךְ הַכּוֹנֵס אוֹ הַחוֹלֵץ לִיבִמְתּוֹ הַמְעֻבֶּרֶת לֹא תִּנָּשֵׂא צָרָתָהּ עַד שֶׁתֵּלֵד זוֹ. שֶׁאֵין הַוָּלָד מַתִּיר עַד שֶׁיֵּצֵא לַאֲוִיר הָעוֹלָם:
כסף משנה
21.
Therefore, when [a man] marries or performs chalitzah with his yevamah who is pregnant, another woman who was married to the deceased husband should not remarry until this woman gives birth. For a child does not remove [the obligation of yibbum] until it emerges into the world.54And the yibbum or the chalitzah performed by the woman is of no consequence whatsoever.

הלכה כב
הַכּוֹנֵס אֶת יְבִמְתּוֹ וְנִמְצֵאת מְעֻבֶּרֶת מַפְרִישִׁין אוֹתָן וּמַמְתִּינִין לָהּ. אִם הִפִּילָה יַחֲזֹר וִיקַיֵּם. וְאִם יָלְדָה אֲפִלּוּ מֵת בַּיּוֹם שֶׁנּוֹלַד הֲרֵי זֶה מוֹצִיאָהּ בְּגֵט וְחוֹלֵץ לָהּ וְאַחַר כָּךְ תִּהְיֶה מֻתֶּרֶת לַאֲחֵרִים. וְאִם נִתְקַיֵּם הַוָּלָד שְׁלֹשִׁים יוֹם אַחַר שֶׁנּוֹלַד הֲרֵי זֶה וָלָד שֶׁל קַיָּמָא וְאֵינָהּ צְרִיכָה מִמֶּנּוּ גֵּט מִפְּנֵי שֶׁהִיא עֶרְוָה עָלָיו:
כסף משנה
22.
[The following laws apply when a yavam] marries his yevamah, and then she is discovered to be pregnant. They should be separated [immediately],55Lest she give birth, in which case she would be forbidden to the yavam. and we wait [to see the results of] her pregnancy. If she miscarries, he should maintain her as his wife.56The Ramah (Even HaEzer 164:5) states that this rule applies only if he marries her before her pregnancy is discovered. If he marries her after her pregnancy is discovered, their relationship should be terminated even if she miscarries.
If she gives birth [different rules apply]: If the child dies, even on the day it was born, the yavam should divorce her, [give her] a get and perform chalitzah with her.57The divorce is necessary lest it appear that a married couple are separating without a divorce, and the chalitzah is necessary as explained in Halachah 5. (See also Chapter 2, Halachah 21.) [Only] then, is she permitted to marry another man. If the child lives for 30 days after its birth,58The Maggid Mishneh states that the same law applies if the child is born with its limbs properly formed after a full-term pregnancy, even if he dies on the day of birth. This ruling is quoted by the Ramah (Even HaEzer 164:6). [the child] is considered to be viable, and there is no need for a divorce, for [relations between the two are forbidden by] a severe prohibition].59She does not require a get, because everyone knows that the consecration of such a woman is not binding.

הלכה כג
יָלְדָה לְאַחַר שִׁשָּׁה חֳדָשִׁים מִשֶּׁנִּתְיַבְּמָה וָלָד שֶׁל קַיָּמָא הֲרֵי זֶה הַוָּלָד סָפֵק אִם בֶּן תִּשְׁעָה לָרִאשׁוֹן אִם בֶּן שִׁבְעָה לָאַחֲרוֹן לְפִיכָךְ יוֹצִיא בְּגֵט וְהַוָּלָד כָּשֵׁר. וְאִם בָּא עָלֶיהָ אַחַר שֶׁיָּלְדָה הַבָּנִים שֶׁיָּבֹאוּ אַחֲרָיו סָפֵק מַמְזֵרִים:
כסף משנה
23.
If she gives birth to a viable child six months after she performed yibbum, there is a doubt whether this child is the son of her first husband and was born after a nine-month pregnancy, or is the son of her [yavam] and was born after a six-month pregnancy. Therefore, [the yavam] should divorce his wife, giving her a get. The child is not, however, considered illegitimate.60For whether he is the son of the woman's first husband or the son of her second husband, no sin was committed in his conception.
If [the yavam] has relations with her after she gives birth, the children that are born afterwards are considered to be of doubtful legitimacy.61For we are unsure whether or not the woman is permitted to remain married to her yavam. The laws governing a person of doubtful legitimacy are discussed in Hilchot Issurei Bi'ah 15:21-22.

נשים הלכות יבום וחליצה פרק א
Nashim Yibum and Chalitzah Chapter 1