Commentary for Kiddushin 127:19

The baraita accords with R. Hisda, in that a father is believed in some matters but not in others. If the father says that the child is old enough to take a vow, or to dedicate or sanctify something to the Temple, or to say that the value of something will go to the Temple, the father is believed. The age required for a person to be able to legally dedicate something is thirteen for a boy, twelve for a girl. But a father is not believed to say that a child is this age, if the consequence will be the punishment of the child.
In all of these cases we can see the rabbis’ famous leniency when it comes to punishments. A witness (the father) might be believed, but the credence the court lends him only extends to non-punishment types of consequences, mostly economic consequences. There needs to be greater evidence before someone can be punished.

As we have learned already, a man has the legal right to betroth his daughter before she reaches majority age. He also has the legal right to accept a get on behalf of his married daughter as long as she has not reached majority age. If the daughter about whom this father is testifying is now a minor, he is believed to say that he betrothed her, or that he betrothed her and then accepted her get, since he currently has the power to perform either activity. The ramification of his being believed to state that he accepted her get, is that she will be disqualified from subsequently marrying a priest.

If she is now an adult (past 12 1/2 years old), he is no longer believed if he makes these statements, since he no longer has the legal right to either accept betrothal or a get on her behalf. We should note that this limits the power of the father over his daughter. Once she is past a relatively young age, he has no legal right to make decisions regarding her kiddushin, nor can he make any statement which would severely impact her status.

A woman who was taken captive is forbidden from subsequently marrying a priest (see Ketubot 2:5). This is because it is assumed that her non-Jewish captors had sexual relations with her and a woman who has had intercourse with a non-Jew is forbidden from marrying a priest. The father is not believed if he states that his daughter was taken captive, no matter how old she is when he offers such testimony. A father does not have the legal right to give his daughter in marriage to a non-Jew and therefore he doesn’t have any special right to testify about this having happened in order to thereby prohibit her to a kohen. Note that when she is a minor the father does have another means by which to prohibit his daughter to the priesthood; he can testify that he betrothed her and then accepted her divorce. Nevertheless, he does not have the right to testify that she was taken captive.

The Talmud explains, as I explained above, that the father is believed when he has the power to marry her off, but not when he does not, when she is of majority age. Similarly, he is not believed in the last clause because he does not himself have the power to disqualify her to the priesthood, neither when she is a minor or an adult.

The Talmud argues—a father does have the power to disqualify his minor daughter by marrying her off to a halal. A halal is the son of a priest who married a woman prohibited to him. According to many rabbis, a woman who has relations with a halal can no longer marry a Kohen. In other words, a father does have the power to disqualify his daughter to the priesthood.
The answer is that our mishnah holds like R. Dostai, an Israelite woman “purifies” the lineage of a halal. Her child will be fit to marry a priest (although the boys are not priests themselves). She herself is also still eligible to marry a priest, should her current husband die. Thus a father does not have the power to disqualify his daughter to the priesthood.

The Talmud argues—a father does have the power to disqualify his minor daughter by marrying her off to a halal. A halal is the son of a priest who married a woman prohibited to him. According to many rabbis, a woman who has relations with a halal can no longer marry a Kohen. In other words, a father does have the power to disqualify his daughter to the priesthood.
The answer is that our mishnah holds like R. Dostai, an Israelite woman “purifies” the lineage of a halal. Her child will be fit to marry a priest (although the boys are not priests themselves). She herself is also still eligible to marry a priest, should her current husband die. Thus a father does not have the power to disqualify his daughter to the priesthood.

An Israelite woman who has sex with a mamzer is disqualified from marrying a priest. So the father could give her in marriage to a mamzer and thereby disqualify her from the priesthood.
The Talmud answers that the mishnah accords with R. Akiva who holds that marriage cannot be contracted between two people prohibited by a negative commandment such as that which prohibits a mamzer from marrying an Israelite woman. Most other tannaim hold that while it is prohibited for a mamzer to marry an Israelite, should the marriage occur, it is valid.

Another difficulty—perhaps the father could marry off his widowed daughter to a high priest, and according to R. Simai, R. Akiva would say that in this case the marriage is valid but that she, and her child, are disqualified from marrying priests.

The Talmud resolves that our mishnah accords with R. Yeshvav, according to whom R. Akiva says that all forbidden marriages, even that of a widow to a high priest create mamzerim. Thus the father cannot marry her off to anyone prohibited to her, because such marriages are not valid.

It is unclear whether R. Yeshvav means to say that even if a man marries a woman who is prohibited by a positive commandment, (such as the prohibition of marrying an Egyptian or Edomite for the first three generation) the child is a mamzer, then our problem is solved. But if all he meant to say is that a widow married to a high priest is a mamzer, then it is still possible for the father to disqualify his daughter by marrying her to someone prohibited by a positive commandment. Such a marriage would be valid and yet she would be disqualified from the priesthood.

R. Ashi now raises a difficulty against the whole interpretation of the mishnah—that a father is believed when he says something happened that he has the power to make happen. A father generally does have the power to betroth his daughter while a minor, but not to divorce her. Furthermore, while he has the power to betroth her, he might not have the power to betroth to a specific man. The other man can always say no, after all. Thus we need another reason why the father is believed or not believed.

R. Ashi uses a verse to prove that a father has the right to prohibit a daughter by making a statement concerning her marriage. The words “I gave my daughter to a man” would prohibit her to everyone. After all, we would not know who married her. The word “this” frees her to be with that man (and after his death or divorce, with any other). This is all accomplished by a mere statement.
However, the father does not have any power to forbid his daughter to the priesthood by declaring that she was taken captive. Therefore, he is not believed.

R. Ashi uses a verse to prove that a father has the right to prohibit a daughter by making a statement concerning her marriage. The words “I gave my daughter to a man” would prohibit her to everyone. After all, we would not know who married her. The word “this” frees her to be with that man (and after his death or divorce, with any other). This is all accomplished by a mere statement.
However, the father does not have any power to forbid his daughter to the priesthood by declaring that she was taken captive. Therefore, he is not believed.

This mishnah discusses a man who offers testimony which will impact his wife’s subjectivity to the laws of yibbum. By stating that he has sons he is exempting her from yibbum. He is believed because if all he wanted to do was exempt her from yibbum he could divorce her. However, he is not believed to state that he has brothers, thereby obligating her for yibbum. Unless we know that he has brothers, he (or others) would have to bring evidence to make his wife subject to yibbum.

The mishnah seems to accord with Rabbi. A husband is believed to make a statement that would permit his wife to remarry without having to undergo yibbum or halitzah (either I have sons or I have no brothers). But he is not permitted to prohibit her, such that she would require yibbum or halitzah (I have no sons, or I have brothers). R. Nathan says he is believed in either case.

The mishnah seems to accord with Rabbi. A husband is believed to make a statement that would permit his wife to remarry without having to undergo yibbum or halitzah (either I have sons or I have no brothers). But he is not permitted to prohibit her, such that she would require yibbum or halitzah (I have no sons, or I have brothers). R. Nathan says he is believed in either case.

Rava said that R. Natan believes him in the baraita because he is retracting a statement at the time of his death. However, in other cases, such as that in the mishnah, where he simply makes a statement, R. Natan would not believe him.

Abaye points out that Rava’s statement does not make sense. If he is believed in the case of the baraita where he contradicts his previous words, all the more so he should be believed in the case of the mishnah, where is not contradicting any previous statement.

Abaye tries to harmonize the mishnah with the baraita by contextualizing both. The mishnah refers to a case where the husband is not presumed to have brothers or sons. He can make a statement such as “I have sons” because that will not make her liable for yibbum. But he cannot change the presumption to make her liable for yibbum by saying “I have brothers.”

The baraita refers to a situation where we thought he had brothers but not sons (making her liable for yibbum). If he is lying in order to exempt her from yibbum, we could ask why he would tell such a lie. He could, after all, just divorce her right before his death and thereby exempt her. Therefore, he is believed to exempt her from yibbum.
Rabbi [Judah Hanasi] would hold that when he said he has no brothers at the time of his kiddushin, he is totally believed, because why would he lie. This overrides the presumption that he had no sons, and now exempts her from yibbum. He will then not be believed later to contradict his words by saying that he does have brothers.
Rabbi Natan says that “why would I lie” is considered like a presumption and one presumption cannot cancel out another. So he was not believed to say he had no brothers at the time of his kiddushin. At the time of kiddushin we maintain that he has brothers and no sons and he cannot later contradict himself at the time of his death by saying either that he has no brothers or that he has sons.