And the same applies to the wife of a brother with whom he did not coexist, i.e., the wife of a man who died before his brother was born. As will be explained, the obligation of levirate marriage does not apply to the yavam in this case. Since levirate marriage does not apply to him, the yevama remains forbidden to him as his brother’s wife. And the last case is if one’s yevama had previously been his daughter-in-law, and after his son had died one’s brother married her, before he too passed away. These fifteen women exempt their rival wives and the rival wives of their rival wives from ḥalitza and levirate marriage forever.

§ And with regard to all of these women listed as prohibited relations, these halakhot apply only if they were married to the deceased brother until the time of his death. However, this is not the case if they died during the deceased brother’s lifetime, or if they refused their husbands when they were minors. This refusal is referring to the decree of the Sages that a girl under the age of twelve whose father is no longer alive may be married off by her mother or brothers. However, this marriage is not final, as she can terminate it by performing an act of refusal, i.e., by declaring, while still a minor, that she does not desire this marriage. In this case, the marriage is annulled retroactively and she is considered as though she were never married at all.

Or if those women were divorced by their husband, the deceased brother, or were found to be a sexually underdeveloped woman [aylonit], i.e., a woman who is so underdeveloped that she is not considered a woman in the full sense, these halakhot do not apply. Her marriage is considered a mistaken marriage and is null and void. In all these cases their rival wives are permitted, as the exemption for rival wives of forbidden relatives applies only when the forbidden relative was the brother’s wife at the time of his death, when the halakhot of levirate marriage came into effect.

§ And the mishna comments that the language of this principle is imprecise, as you cannot say with regard to his mother-in-law and with regard to his mother-in-law’s mother and with regard to his father-in-law’s mother that they were found to be an aylonit, as an aylonit is sterile and therefore cannot become a mother or a mother-in-law. Nor is the mishna precise when it states: Or refused, as refusal applies only to minors, who cannot give birth.

§ The mishna explains: How do these women exempt their rival wives? If, for example, his daughter or any one of those women with whom relations are forbidden was married to his brother and this brother had another wife, and the brother died, then just as his daughter is exempt from levirate marriage, so too her rival wife is exempt. If his daughter’s rival wife subsequently went and married his second brother, to whom she is permitted, and he had another wife, and he died childless as well, which means that his wife comes before the first yavam, the daughter’s father, for levirate marriage, then just as his daughter’s rival wife is exempt, so too the rival wife of her rival wife is exempt.

The mishna adds: Even if they are one hundred brothers, the same logic applies. If a woman is exempt from levirate marriage because she is the rival wife of a forbidden relative or the rival wife of a rival wife of this kind, and she herself has an additional rival wife, this rival wife is also exempt and in turn exempts her own rival wives from levirate marriage.

How so? What are the cases in which if they died their rival wives are permitted? If, for example, one’s daughter or any one of those women with whom relations are forbidden was married to his brother, and this brother had another wife, and then his daughter died or was divorced and afterward his brother died, her rival wife is permitted to him.

§ The mishna states another principle: And if any of these forbidden relatives was a minor who could refuse her husband, then even if she did not refuse, her rival wife performs ḥalitza and does not enter into levirate marriage. The rival wife may not enter into levirate marriage, as she is the rival wife of a forbidden relative. However, she is not entirely exempt from levirate marriage and must be released by ḥalitza because the marriage of the forbidden relative was not a fully valid marriage, and therefore, by Torah law, the other woman is not considered a rival wife of a forbidden relative.

GEMARA: The Gemara asks a question with regard to the order of the mishna’s list: Now, since the halakha that all these women with whom relations are forbidden are exempt from levirate marriage and exempt their rival wives is derived from the case of a wife’s sister, as demonstrated later, let the mishna teach the case of a wife’s sister first and only afterward mention the other instances, which are derived from that halakha.

And if you would say that the tanna cited the cases in order of severity, then you must say that it is in accordance with the opinion of Rabbi Shimon, who says that execution by burning is more severe than stoning. For this reason, the tanna began with the cases of one’s daughter and his daughter’s daughter and his son’s daughter and so forth, since one who has relations with these women is punished by burning, after which the tanna listed those cases that entail a lesser penalty.

However, the Gemara argues that even so, the order of the mishna remains problematic. If so, let him teach the case of one’s mother-in-law first, as the main transgression that entails burning is written with regard to his mother-in-law, as it is stated: “And if a man take with his wife also her mother, it is wickedness; they shall be burnt with fire, both he and they” (Leviticus 20:14). And furthermore, after his mother-in-law let him teach his daughter-in-law, as after execution by burning, stoning is the most severe of the other capital punishments imposed by the courts.

Rather, the Gemara retracts the previous explanation in favor of the following: With regard to his daughter, since this prohibition is actually derived from a homiletical interpretation and is not explicitly stated in the Torah, it is therefore dear to the tanna. Consequently, he listed this novel case of a daughter first.