2,812. Vows With Time Constraints

Hilchos Nedarim 10:11

If someone prohibits himself something until “the rains,” he is prohibited until the start of the rainy season in Israel, which is Rosh Chodesh Kislev. Once the rainy season arrives, he becomes permitted regardless of whether or not it rains. However, if it rained from 17 Marcheshvan, he becomes permitted. If he says, “until it rains,” then he’s prohibited until it rains, so long as it rains from the second portion of the rainy season, which in Israel and places near it is from 23 Marcheshvan and on. If he specified “until the rains stop,” then he’s prohibited until the end of Passover in Israel and places like it.

Hilchos Nedarim 10:12

If a person imposes a vow on his wife in Marcheshvan, telling her that she may not benefit from him from then until Passover if she goes to her father’s house from then until Succos, she is immediately prohibited to benefit from him. This is an enactment out of concern that she might go. If she went before Passover and benefitted from her husband before Passover, he is liable to lashes (for letting her benefit from him, counter to his vow). After Passover, even though the condition no longer applies, it is prohibited for him to treat the vow lightly by letting her to go to her father’s home and benefitting from him. Rather, he should act as if it’s prohibited until Succos as per his vow. This is so even though he predicated his vow on a time that has now passed. The same is true in all comparable cases. If she went to her father’s home after Passover, she is not prohibited to benefit from her husband.