Ketubot, Chapter Seven, Mishnah Two
Whereas in yesterdays mishnah the husband tried to prevent his wife from benefiting from his property, in todays mishnah he takes a to try to prevent her from eating any produce whatsoever. This is obviously a much more expansive vow.
We should note that the Talmud explains this mishnah as a case where the wife took the vow not to eat a certain fruit and the husband did not annul the vow, as is his right (see Numbers 30:11-15). The reason why the Talmud explains the mishnah in this way is that a person can never take a vow to forbid another person to do something if it has nothing to do with his (the one who vowed) property. In other words while Reuven can take a vow that Shimon cant eat any of Reuvens bread, Reuven cannot take a vow that Shimon cant eat bread. Therefore, our mishnah must deal with a case where the woman vowed and the man did not break the vow.
I will explain the mishnah more according to its words than its explanation in the Talmud. If we understand the mishnah without the Talmuds explanation, we will need to conclude that a husband can take a vow to forbid his wife from doing anything; however, if he does so he will need to divorce her immediately.
1) If a man forbade his wife by vow from tasting any kind of produce he must divorce her and give her the ketubah.
2) Rabbi Judah ruled: if he was an Israelite he may keep her [as his wife, if the vow was] for one day, but must divorce her and give her the ketubah [if it was for] two days.
a) If he was a priest he may keep her [as his wife, if the vow was] for two days, but must divorce her and give her the ketubah [if it was for] three.
Section one: According to the first opinion in the mishnah, if a man vows that his wife cannot eat any type of produce, he must divorce her immediately. In this case he is not given any cooling off period, because his vow was so damaging.
Section two: Rabbi Judah gives the man a day to cool off (and two for a priest, who cannot remarry his divorcee) but no more. Again, since the vow was so inclusive, and she can only go for so long without eating produce, he must divorce her quite quickly.