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 wife 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. It is possible for his paternal brother to marry his maternal sister or his mother's sister (because they are not related).

(d) We learn from the Pasuk "Ki Yeishvu 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.

(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 an Ervah.

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

(c) We learn from the Pasuk "Ki Yeishvu 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 be'Olamo.

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

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 Miy'un or was discovered to be an Aylonis.

(c) In spite of the fact that Miy'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 be'Chayei ha'Av' (a girl whose father married off as a Ketanah, and who became divorced, when she still a Ketanah and) who (then) married herself to the brother of the person concerned.

(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 Miy'un - because once a woman has a child she is neither an Aylonis nor a Ketanah (and Miy'un only applies by a Ketanah).

(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 "ve'Ishah el Achosah Lo Sikach *li'Tz'ror* ... " - that a Tzaras Ervah exempts her Tzarah, too.

(c) 'Afilu Hein Mei'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.

7)

(a) The Tzarah of any woman who is able to make Miy'un but does not do so, is obligated to perform Chalitzah - because, seeing as her Kidushin is only mi'de'Rabbanan, it does not have the power to remove the Zikah (the tie between the Yavam and the Yevamah), which is d'Oraysa.

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

(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 order of stringency.

(c) We ask two Kashyos on this: one, that in that case, 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) The second Kashya is: in that case, after Chamoso, the Tana should have learned the case of Kalaso - who is Chayav stoning, the second most stringent punishment, according to Rebbi Shimon.

(a) We therefore retract from the previous suggestion. 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 P'tur 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 dearer in the eyes to the Tana than the other case of Arayos (which are all written explicitly).