Nedarim 72 - 78
“But he (the husband) didn’t hear the vow!”
The gemara asks this question regarding a scenario where the husband appointed a guardian agent to annul his wife’s vows. However, this question seems difficult to understand, since the agent did in fact hear the vow, and there is an accepted rule that “the agent of a person is like the person”, and the agent’s hearing should suffice. One approach to understand the question is that it is not logical that the agent should have the ability to do something that that husband who appointed him cannot do. If this were true, the agent would be “greater” than the one who appointed him and not merely “like” that person. (Harav Rav Yossi in Tosefot as cited by Rabbeinu Nissim)
- Nedarim 72b
Rav Dimi the brother of Rav Safra taught, "Whoever makes a neder (vow) is called a ‘sinner” even if he fulfills the vow.”
This teaching is derived in our gemara by Rav Zvid from a verse that states, “and when you refrain from vowing, you will not have a sin” (Dev. 23:22), implying that if a person makes a vow he has a sin by virtue of making the vow. (Shulchan Aruch Yoreh De’ah 203:1)
- Nedarim 77b