1)

(a)Fifteen women exempt their Tzaros and their Tzaros' Tzaros from Chalitzah and from Yibum. 'Exempt their Tzaros' means - that should one of them be married to his brother, then both she and any other woman to whom the brother is married, is Patur from Yibum.

(b)The list includes 'his wife's daughter, her son's daughter and her daughter's daughter; his daughter, his daughter's daughter and his son's daughter must be speaking about the daughter and granddaughter of a woman whom he raped (or seduced) - because the daughter or granddaughter of a woman whom he married is included in his wife's daughter or granddaughter (since it makes no difference whether his wife's daughter is from another man or from him).

(c)His mother-in law, her mother and his father-in-law's mother are also included in the exemption, and so are his sister and his mother's sister. There is no reason why his paternal brother should not marry his maternal sister or his mother's sister, seeing as they are not related.

(d)We learn from the Pasuk "Ki Yeshvu Achim Yachdav" - that a brother is obligated to perform Yibum, even if he is a brother from his father's side only, and not from his mother's.

2)

(a)The exemption also applies to his wife's sister, and his maternal brother's sister. We learn from the Pasuk "Ervas Eishes Achicha" - that a maternal brother as well a paternal one, is considered an Ervah.

(b)The last two cases in the Mishnah are Eishes Achiv she'Lo Hayah b'Olamo and Kalaso. The case of Eishes Achiv she'Lo Hayah b'Olamo is - that of Reuven who died without children, and Shimon (a brother who was Reuven's contemporary) performed Yibum with Reuven's wife, but only after Levi (a younger brother) was born. When Shimon dies, Levi is forbidden to perform Yibum with Reuven's former wife.

(c)We learn from the Pasuk in Ki Setzei "Ki Yeshvu Achim Yachdav" - that one only performs Yibum with the wife of a brother who is a contemporary, but not with an Eishes Achiv she'Lo Hayah b'Olamo.

(d)A person who performs Yibum with any of the above fifteen women - is Chayav Kares.

3)

(a)The wife of a brother who has children, the wife of Reuven's brother who died before Reuven was born and the wife of a maternal brother - are all wives of brothers who are precluded from Yibum, and are therefore punishable by Kares.

4)

(a)If any of the fifteen women die or are divorced before her husband dies - the Tzarah will be obligated to perform Yibum after the death of her husband.

(b)The same will apply if she made Mi'un or was discovered to be an Aylonis (who was unable to have children).

(c)In spite of the fact that Mi'un normally refers to a girl whose father died and who was married off by her mother or brother - the case of 'Bito' will still apply in our Mishnah, by a 'Yesomah b'Chayei ha'Av' (a girl whose father married her off as a Ketanah, and who became divorced, when she was still a Ketanah and) who (then) married herself to the brother of the current Yavam.

(d)It is not possible to say in our Mishnah that his mother-in-law, her mother or his father-in-law's mother was an Aylonis or made Mi'un - because once a woman has a child she can neither be an Aylonis nor a Ketanah (and Mi'un only applies by a Ketanah).

5)

(a)When the Tana says that the Arayos in our Mishnah 'exempt their ...

1. ... Tzaros' - he means that if his brother had another wife when he married the woman in question, then, when he dies, neither of the two women are Chayav Yibum.

2. ... 'and their Tzaros Tzaros' - he means that if another brother made Yibum with the Tzarah and died, then not only is the Tzarah Patur from Yibum, but so is any other wife of his.

(b)We learn from the Pasuk in Acharei-Mos "v'Ishah el Achosah Lo Sikach li'Tzeror ... " - that a Tzaras Ervah exempts her Tzarah, too (as we just explained).

(c)'Afilu Hen Me'ah' means - no matter many how brothers there are, even a hundred, each time one of the brothers performs Yibum with the previous woman's Tzarah, her Tzaros enter the prohibition.

(d)We learned earlier that if the Ervah died or was divorced before her husband, the Tzarah is obligated to perform Yibum. This is because - she was not a Tzaras Ervah at the time when she fell to Yibum.

6)

(a)We learn from the Pasuk in Ki Setzei " ... Asher Lo Yivneh es Beis Achiv" - that a Yavam is obligated to build one house, and not two. Consequently, if a man dies leaving behind two widows, once the Yavam has performed Yibum or Chalitzah with one of them, the second Tzarah is permitted to get married immediately.

7)

(a)The Tzarah of a woman who is able to perform Mi'un but did not do so, remains obligated to perform Chalitzah - because, seeing as her Kidushin is only mid'Rabanan, it does not have the power to remove the Zikah (the tie between the Yavam and the Yevamah), which is d'Oraisa.

(b)Nevertheless, Chazal forbade her to make Yibum - because she resembles a Tzaras Ervah.

8)

(a)The Torah teaches us the exemption of the Arayos from Yibum - by Achos Ishto.

(b)To answer the Kashya why the Tana then begins with the case of Bito, rather than with Achos Ishto, we suggest that the author of our Mishnah is Rebbi Shimon - who holds that the death of burning is more stringent than that of stoning. Consequently, he opens the Mishnah with Bito, whose punishment is burning, in order to follow the sequence of stringencies.

(c)We pose two questions on this suggestion however: Firstly, if that is so, the Tana should have begun with the case of Chamoso - because that is where the Torah explicitly writes the punishment of burning, rather than with Bito.

(d)Secondly, if that were the case, then after Chamoso, the Tana ought to have learned the case of Kalaso - who is sentenced to stoning, the second most stringent punishment, according to Rebbi Shimon.

9)

(a)We therefore retract from the previous suggestion, concluding that the Tana opens with the case of Bito - because it is derived from a Derashah (as opposed to all the other Arayos, which are written explicitly in the Torah), and is therefore dear in the eyes of the Tana.

(b)As far as the Petur Yibum is concerned, all the cases of Ervah are learned from Achos Ishah. Nevertheless, Bito is different, inasmuch as the very fact that Bito is an Ervah, is learned from a Derashah, making it more precious to the Tana than the other case of Arayos (which are all written explicitly).