OPINIONS: The Gemara records a dispute between Rebbi Nasan and the Chachamim with regard to whether the husband may annul a Neder which his wife made but which has not yet taken effect. The RAN (end of 90a) cites differing opinions about which Nedarim are subject to the dispute between Rebbi Nasan and the Chachamim. One opinion maintains that the dispute applies only when the Neder was made with a Tenai, contingent upon the occurrence of another event. When, however, the condition merely gives a time-delay to the Neder, even Rebbi Nasan agrees that it is considered as though the Neder has already taken effect and it therefore may be annulled. Another opinion maintains that even if the condition merely gives a time-delay to the Neder (for example, she said that she wants the Neder to take effect after a certain period of time passes), Rebbi Nasan still maintains that the husband cannot annul the Neder.

Aside from the question of what keeps the Neder from taking effect presently, there is the other question of what type of conditional Neder may the husband annul.

(a) The RAN at the beginning of this Perek (80a) writes that even the Chachamim do not allow the husband to annul every Neder made with a Tenai, even if the eventual Neder involves Inuy Nefesh. The Ran explains that in order for the Neder to be able to be annulled by the husband, the Neder must meet one of the following criteria:

1. The Tenai must entail Inuy Nefesh as well (like the Neder of "Netulah Ani Min ha'Yehudim Im Eshamshach," where fulfillment of the Tenai also involves Inuy Nefesh). (The same applies when the Tenai involves Devarim she'Beino l'Beinah; see Ran to the Mishnah, 89b.)

2. It is unlikely that she will be able to fulfill the condition. In such a case, it is considered as though there already is Inuy Nefesh. The Neder of the Mishnah is included in this category: When she says, "I should become prohibited to derive benefit from you if I serve my father," it is assumed that she will not be able to fulfill the condition.

3. It is not in her hands to fulfill the condition. All Nedarim which will take effect only if she is divorced are included in this category. Since her husband may divorce her at will, she is no longer in control of the Neder and it is considered as if it has already taken effect.

Nedarim which do not meet any of the above criteria cannot be annulled until they actually take effect, even according to the Chachamim.

(b) The RAMBAM (Hilchos Nedarim 12:12) does not make the above distinctions. He apparently maintains that the husband may always annul a conditional Neder notwithstanding the nature of the Tenai.

(c) The TUR (YD 234) writes that both of the Nedarim of the Mishnah (cases in which the woman either prohibits upon herself the Hana'ah of the husband if she serves her father, or she prohibits herself to her father if she serves her husband) fall into the category of Devarim she'Beino l'Beinah. The first case is Beino l'Beinah because the wife's disallowance to serve her father causes embarrassment to the husband. The second case is Beino l'Beinah because he suffers embarrassment from the fact that by serving him she becomes prohibited to her father.

From the words of the Tur it is evident that the Tenai must also entail Devarim she'Beino l'Beinah in order for the husband to be able to annul the Neder, even if the Neder itself is of the type which he may annul.