(Mishnah): If a man said 'I was Mekadesh my daughter', or 'I was Mekadesh her and received her Get', if she is still a minor (or Na'arah), he is believed;

If he said that he was Mekadesh her or received her Get when she was a minor, and now she is an adult (Bogeres), he is not believed.

If he said 'she was captured and I redeemed her (she is forbidden to Kohanim)', he is never believed.

(Gemara) Question: Why is he believed when she is a minor, and not when she is an adult?

Answer #1: When she is a minor, he can marry her off, so he is believed about this;

When she is an adult, he cannot do this. He may never hand her over to captors (therefore he is not believed about these).

Question: He can forbid (a minor) to Kohanim in another way. He can marry her to a Chalal!

Answer: Our Mishnah is like R. Dostai ben Yehudah, who says that a Bas Yisrael is Machshir (children of) a Chalal (and she remains permitted to Kohanim).

Question: He can forbid (a minor) to Kohanim by marrying her to a Mamzer!

Answer: Our Mishnah is like R. Akiva, who says that Kidushin is not Tofes between Chayavei Lavin (when a Lav forbids Bi'ah).

Question: According to R. Simai, even R. Akiva admits that he can marry her (if she is widowed) to a Kohen Gadol, and this will forbid her to Kohanim!

(Beraisa - R. Simai): R. Akiva says that children from all forbidden Bi'os (of Chayavei Lavin) are Mamzerim (and Kidushin is not Tofes), except for (Isurei Kehunah, e.g.) a widow married to a Kohen Gadol, for the Torah says "he will not take... and he will not profane";

He makes his children profaned (Chalalim), but not Mamzerim.

Answer: Our Mishnah is like R. Yesheivav, who says that R. Akiva says that any forbidden relationship between Yisre'elim produces Mamzerim.

Question: This answer works if R. Yesheivav taught this by itself (it applies in all cases);

However, if R. Yesheivav came to argue with R. Simai (who says that Chayavei Lavin of Kehunah do not make Mamzerim), R. Yesheivav only discusses Lavim, but he admits that Bi'ah forbidden by an Aseh do not make Mamzerim! (A man could marry his daughter off in such a marriage to disqualify her.)

Objection (Rav Ashi): Do not say that the reason the father is believed in the Reisha is because it is in his power. He is believed also about divorce, and this is not his decision!

Also, he cannot force a man to marry his daughter!

Answer #2 (Rav Ashi): Regarding Kidushin and divorce, the Torah believes the father;

(Rav Huna): "I gave my daughter to this man" teaches that a man is believed about his daughter's Kidushin;

When he says 'I gave', he forbids her. When he said 'to this man', he permits her to him.

The Torah believed the father about Kidushin, but not regarding captivity.

(Mishnah): If a dying man said 'I have children' (so my wife will not fall to Yibum), he is believed;

If he said 'I have brothers' (so she will fall to Yibum), he is not believed.

(Gemara) Inference: He is believed to permit, but not to forbid.

Suggestion: Our Mishnah is not like R. Nasan:

(Beraisa - Rebbi): If at the time of Kidushin, Reuven said 'I have no children', and at the time of death he said 'I have children', or at the time of Kidushin he said 'I have no brothers'; and at the time of death he said 'I have brothers', he is believed to permit, but not to forbid;

R. Nasan says, he is believed even to forbid.

Rejection #1 (Rava): The Beraisa is different. Since at the time of death he contradicted what he said earlier, surely he is not lying.

Objection (Abaye): All the more so we should be concerned lest he is lying!

In the Mishnah, even though he does not contradict himself, he is not believed to forbid. All the more so in the Beraisa, when he contradicts himself, he should not be believed to forbid!

Rejection #2 (Abaye): In the Mishnah, the Chazakah was that the man had no children or brothers (so his wife will not fall to Yibum). When he says that he has children, this supports the Chazakah (about his wife), so he is believed;

When he says that he has brothers, this opposes the Chazakah (about his wife), so he is not believed.

In the Beraisa we had a Chazakah that Reuven had brothers but no children (so his wife will fall to Yibum). He would not lie (at the time of Kidushin) to exempt her from Yibum, for he could divorce her (Rashi - immediately; Tosfos - he could write a Get now, to divorce her right before he dies).

Rebbi holds that this reasoning (he would not lie if he can achieve his goal without lying) is as strong as witnesses, so it overturns the original Chazakah (so he is not believed to say as he dies that she falls to Yibum);

R. Nasan holds that this reasoning is like a Chazakah. It does not override the original Chazakah (so he is believed to forbid at the time of death).

(Mishnah): If one was Mekadesh his daughter without specifying which one, surely, he did not Mekadesh his Bogros (adult daughters).

R. Meir says, if a man has two sets of daughters (from different wives), and know that he was Mekadesh his big daughter, but he is unsure if this was the oldest of the older set, or the oldest of the younger set, or the youngest of the older set who is older than all of the younger set, all are doubtfully Mekudeshos, except for the youngest of the younger set;

Rebbi Yosi says, he was definitely Mekadesh the oldest of the older set.

R. Meir says, if he was Mekadesh his little daughter, but is unsure if this was the youngest of the younger set, or the youngest of the older set, or the oldest of the younger set who is younger than all of the older set, all are doubtfully Mekudeshos, except for the older of the older set;

Rebbi Yosi says, he was definitely Mekadesh the youngest of the younger set.

(Gemara) Inference: We are sure that he was not Mekadesh his adult daughters, but his minor daughters are Safek Mekudeshos!

This shows that Kidushin that forbids Bi'ah (each girl is Safek Achos Ishto) is valid Kidushin!

Rejection: No. The case is, there is only one Bogeres and one minor (or Na'arah) daughter.

It says Bogros (plural) because whenever this occurs, the Bogeres is always permitted.

Question: This is obvious (one cannot be Mekadesh his Bogeres)!

Answer #1: The case is, she made him a Shali'ach to be Mekadesh her;

The Mishnah teaches that we are sure that he did something he benefits from (he keeps the Kidushin money for his minor daughter), and not something he does not benefit from.

Objection: Surely, the Mishnah discusses even when the Bogeres told him that he can keep her Kidushin money!

Answer #2: Still, we are sure that he did a Mitzvah incumbent on him, (to be Mekadesh his minor daughter), and not something not incumbent on him (being Mekadesh his Bogeres).

(Mishnah): If a man has two sets of daughters...

The Mishnah needed to teach about Kidushin of his big daughter and of his small daughter.

Had it taught only about 'my big daughter', one might have thought that R. Meir holds that one calls this to any daughter who is not the youngest of all, but he would admit that he would call only the very youngest 'my small daughter';

Had it taught only about 'my small daughter', one might have thought that Rebbi Yosi holds that he calls this only to the very youngest, but he admits that one calls 'my big daughter' any one who is not the youngest of all.

Inference: R. Meir holds that one (has intent that causes that he) enters Safek, and Rebbi Yosi says he does not.

Contradiction (Mishnah): If one vowed 'until Pesach', he is forbidden until Pesach begins;

If he said 'until it will be Pesach', he is forbidden until the end of Pesach;

R. Meir says, if he said 'until Pnei (the face of) Pesach', he is forbidden until Pesach begins (for before Pesach faces all of Pesach);

Rebbi Yosi says, he is forbidden until the end of Pesach (perhaps he meant any time that faces some part of Pesach, even the last moment).

Answer (R. Chanina bar Avdimi): The text of the Mishnah of vows must be corrected. The opinions of R. Meir and Rebbi Yosi must be switched.

Support (Beraisa - R. Meir): The rule is, if something has a fixed time, and one said 'Pnei', he is forbidden until it ends;

Rebbi Yosi says, he is forbidden until it begins.

(Abaye): The argument in our Mishnah is only when he has two sets of daughters. If he has only one set, all agree that 'big' refers to the oldest, and 'small' refers to the smallest. He calls his middle daughter by her name.

Question (Rav Ada bar Masnah): If so, in our Mishnah, the middle daughter of the younger set should be permitted (when he said 'my big daughter')!

Answer: The case is, there are only two daughters in the younger set.

Support: If there were more, the Mishnah should say that they are forbidden!

Question: You must admit that middle daughters in the older set are forbidden, but the Mishnah does not teach them!

Answer: There was no need to teach about them. Since we taught that even the youngest of the older set is forbidden, surely middle daughters of the older set are also forbidden!

However, if middle daughters of the younger set were forbidden, this must be taught!

Question (Rav Huna Brei d'Rav Yehoshua): 'Pnei Pesach' is analogous to one set of daughters, and the middle days are forbidden!

Answer (Rava): There, they argue about the word 'Pnei';

The opinion that permits the middle days says that Pnei means facing (before). The opinion that forbids the middle days says that Pnei Pesach means 'until Mifnei (passes) Pesach.