Nedarim 85: Benefit of Discretion; What Does Not Yet Exist

The rabbis discuss the principle of tovat ha'na'a, the benefit of discretion.  According to this principle, there is no monetary value attached to a gift where one is allowed to choose to whom one gives a gift.    This limits the potential positive consequences that one might incur due to giving a gift.  Our notes in Steinsaltz teach that a man cannot betroth a woman with priestly gifts that he has set aside - they have no monetary value, and a betrothal requires that exchange.  Further, if a priest acquired such a gift without the owner's knowledge, he need not return the gift - it has no monetary value.  Finally, we learn that we cannot use the benefit of discretion in exchange for any item.

The rabbis discuss this principle in relation to gifts where teruma and tithes may or may not have been separated.  If a thief steals produce that has not been separated, who is to be penalized, the thief or the owner?  The owner should have separated the gifts and put them aside so that they would not be stolen in the first place.  Further, tithes are prohibited to anyone but priests.  Thus they are of no monetary value to a thief.  The rabbis ask further questions about this as well.  

We learn a new Mishna: If a woman vows that she will not produce anything for her father, her brother, her husband's father or her husband's brother, as it is konam for her, her husband cannot nullify her vow.  This vow does not affect her relationship with her husband nor does it cause her affliction.  And if she vows that she will not produce anything for her husband, including the work that she is obliged to do for him - that it is konam for her - he does not need to nullify her vow.  She is not permitted to keep that promise.  Rabbi Akiva comments: her husband should nullify her vow in case she exceeds the required amount of work she is to do for him.  Rabbi Yochanan ben Nuri says that he should nullify her vow because he might divorce her one day and she will be forbidden to him forever at that time (as her vow will come into effect upon their divorce which will ensure that they do not remarry).

Shmuel agrees with Rabbi Yochanan ben Nuri, and so the rabbis ask if he believes that one cannot consecrate an entity which does not yet exist.  The Gemara goes back to an argument in Masechet Ketubot where Shmuel agrees that a wife's earnings beyond what she keeps to sustain herself should not become consecrated earnings - the couple cannot make such an arrangement for she has not yet earned the surplus income.  However, the reason that these earnings are considered non-sacred is because Shmuel believes that they should belong to her husband. If that money belongs to her husband and not to her, how can she make a vow regarding that property?  I will note here that Rabbi Akiva believed that any surplus earnings should belong to the wife herself.

Rav Yosef believes that konamot suggest a different circumstance.  Not only can a person state that another person's property is konam for them, s/he can also vow that s/he is prohibited from benefiting from an entity that does not yet exist. 

The rabbis argue about this point as well.  And Rav Huna, son of Rav Yehoshua, suggests that perhaps we are speaking of a woman who says that her hands are consecrated to the One who made them.   Thus we are not even referring to an entity that has not yet come into the world, as her hands are already here.  And of course, we understand this to mean 'the work of her hands'.  The Gemara argues that a woman's hands are in fact consecrated to her husband.  Without skipping a beat or asking a question, the rabbis add to this point.  She might have added the caveat, "when I will be divorced" to her vow.  Of course, such a vow could not be effective as she is not currently divorced and she might not become divorced.