Nedarim 3:1-2

Nedarim 3:1

Four types of vows were ruled non-binding by the Sages: vows to make others comply, exaggerated vows, accidental vows and vows of compulsion. An example of a vow to make others comply is a seller who says, “Konam I don’t reduce this price for you to under a sela” and a buyer who says, “Konam I don’t pay you more than a shekel” when both of them really want to agree to three dinar. Rabbi Eliezer ben Yaakov also includes one who wants to persuade his friend to come for a meal by taking a vow. Each year one says that any vows he may take are void, though he must remember this at the time of taking a vow.

Nedarim 3:2

An example of an exaggerated vow is if one says, “Konam if I didn’t see as many people on this road as left Egypt,” or “if I didn’t see a snake as large as the beam of an olive press.” An accidental vow is if one swears that he didn’t eat or drink and then he remembers that he did, or if he prohibits his wife from benefitting from him because she stole his wallet or struck their son and then it turns out that she didn’t do the thing that he thought she did. If he saw some people eating his figs and he said, “They’re like a sacrifice to you” (i.e., prohibited), then it turned out that the group included his father and brothers along with other people, Beis Shammai say his relatives are permitted but the others are prohibited while Beis Hillel say that everyone is permitted.