Commentary for Kiddushin 86:16

Just as agents can be witnesses for marriage, so too they can for divorce or monetary cases.

The Talmud now explains why R. Nahman needed to teach that agents can also be witnesses in all three fields of law.
If the law had been stated about betrothal, I might have thought that he is believed because betrothal makes her prohibited to him. But divorce would make her permitted to him. So maybe we wouldn’t believe him to say that he had been sent to divorce her.

If R. Nahman had taught us about divorce, we might have thought that the agents are believed to be witneseses because both witnesses cannot marry the woman. There is less fear of collusion. But they could both lie about a monetary matter and share the illicit proceeds.

There is a dispute among amoraim whether or not when one takes a loan in front of witnesses he must also repay in front of witnesses. If he does, then these agents are interested witnesses. They would want to say “we did repay him” because otherwise the sender will claim the money back, since there are no witnesses to say that they (the agents) gave him the money back. In other words, these agents have an incentive to lie.

Rava holds that one need not pay back a creditor in front of witnesses. These agents would be believed to say that they had returned the money to the sender. Therefore, since they have no incentive to lie, they are believed to say that they did indeed give it to the creditor.

The rabbis instituted that when one completely denies a monetary claim the one denying must take an oath that he does not owe money. If the agents claim that they returned the money to the sender, they would have to take an oath. Therefore, they have an incentive to say that they gave the money to the creditor, and such their testimony is not believed. To be believed they must take an oath that they indeed gave the money to the creditor (the person to whom they were sent to give the money). If the creditor then takes an oath that he has not received the money, the sender will have to repay him the money. In short, do not send out agents if you do not trust them.

The Talmud quotes a mishnah from Gittin. According to the first opinion, a betrothed girl who is between 12 and 12.5 years of age, a na’arah, can either receive her own get or her father can. R. Yehudah holds that only her father can receive the get. And if she is so young (or mentally incapacitated) that she cannot hold on to her get, then she cannot be divorced.

According to Resh Lakish, the same dispute that occurs with regard to divorce all occurs in betrothal. The first opinion would hold that a na’arah can betroth herself or her father can betroth her, while R. Yehudah would hold that only the father can.

Why does R. Yohanan say that when it comes to divorce, either she or her father can accept the get, whereas when it comes to betrothal, since it removes her from her father’s domain, only he can accept it, not her? The issue hinges on whether the act brings her into her father’s domain (either can accept) or takes her out of her father’s domain (only the girl can accept).

Above we said that for a na’arah, only her father can betroth her since kiddushin takes her out of his domain. But this mishnah says that when it comes to “ma’amar” betrothal for a girl awaiting levirate marriage, either she or her father can accept it, despite the fact that this also takes her out of her father’s domain. This is a difficulty on R. Yohanan.