Shalom Daniel,

The foundational principle here is that there is no formal Mitzvas Aseh that obligates a man to remarry his ex-wife. Rather, it is considered an important and praiseworthy matter, and perhaps even carries the spirit of a Mitzvah in terms of restoring Shalom Bayit or acting with kindness, yet it does not constitute a Torah obligation that would invalidate a Neder or Shevu'ah. Nowhere in the Torah do we find a command requiring a man to remarry his divorced wife as long as she has not married another, and therefore if a man makes a Neder or Shevu'ah not to remarry his ex-wife, it cannot be said that such a vow is inherently null because it opposes a Mitzvas Aseh.

Indeed, the Sefer ha'Chinuch (Mitzvah 580) states simply that before she marries another, "it is permitted to remarry her, and it is even appropriate to do so," meaning that it is a worthy and proper action, but not a binding Torah obligation. However, other Poskim, such as Rabeinu Shimon ben Tzemach Duran in Shu't Tashbetz (3:9), the Radbaz in Shu't Radbaz (8:153), and Rabeinu Shmuel Vital in Shu't Be'er Mayim Chayim (Siman 80), discussed precisely the case where a man made a Shevu'ah not to remarry his ex-wife, and debated whether such a Shevu'ah could be annulled due to the value of the matter. From their discussions, it is clear that even if there is merit and value in remarrying the ex-wife, since there is no binding Mitzvas Aseh the Shevu'ah certainly takes effect initially, and only afterward might there be grounds for Hataras Nedarim or Shevu'os based on concerns for promoting Shalom Bayit.

The Radbaz explicitly wrote that there is no obligatory Mitzvah here, explaining that where there was a Neder between them not to remarry it demonstrates previous discord and strife. On the other hand, Rabeinu Shmuel Vital maintained that remarrying the ex-wife is a great Mitzvah, especially when they have children together, and based his view on the Midrash (Vayikra Rabah 34:14), which tells that Rebbi Yosi ha'Glili supported his divorced wife and her new husband for the rest of their lives, deriving this from the verse "umi'Besarcha Lo Tis'alem" (Yeshayahu 58:7). From this Midrash, Rabeinu Shmuel Vital infers that all the more so there is a Mitzvah for a man to remarry his ex-wife.

Nonetheless, it is evident from all the sources that there is no Torah-commanded Mitzvas Aseh that would retroactively invalidate the Shevu'ah. The entire discussion revolves only around whether it would be proper to annul the vow afterward, based on considerations of repentance and promoting peace.

Therefore, it is straightforward and clear that a Neder or Shevu'ah not to remarry one's ex-wife remains valid according to Halachah, and there is no basis to challenge its validity on account of any supposed contradiction to a Mitzvah.

Kol Tuv,

Aharon Steiner

Shalom Daniel,

Thank you for your follow-up question. If I understand you correctly, you are asking the following: Based on what I wrote that remarrying one's ex-wife is not a formal Mitzvas Aseh but rather a proper or advisable action, why then does an Anas not receive Malkus when he divorces his wife? After all, as we said, there is no binding Mitzvas Aseh to remarry her, so the prohibition "Lo Yuchal l'Shalchah" should no longer be classified as a Lav ha'Nitak la'Aseh.

My answer is as follows:

You are correct in saying that there is no Mitzvas Aseh obligating the man to take back his ex-wife as such -- meaning, the regular case of a divorced couple. However, the case of Ones is different. The unique Mitzvah of v'Lo Siheyeh l'Ishah still remains in force. That Mitzvah is not canceled by the fact that he divorced her; it still stands and, therefore, the Lav of Lo Yuchal l'Shalchah continues to be categorized as a Lav ha'Nitak la'Aseh.

This is in contrast to the case of Machzir Gerushaso, where, as we discussed, there is no actual Mitzvas Aseh, but rather a moral or appropriate course of action.

Accordingly, even after the Anas divorces the woman, the positive commandment of v'Lo Siheyeh l'Ishah continues to apply; thus, the prohibition remains a Lav ha'Nitak la'Aseh, and he does not receive Malkus for the divorce.

Kol Tuv,

Aharon Steine

Shalom Daniel,

Your current question raises an important point that we had not yet addressed directly. Until now, our discussion focused on whether there is a binding Mitzvas Aseh in cases such as Machzir Gerushaso or Anusah, and how that affects the classification of the associated Lav as a Lav ha'Nitak la'Aseh. What we did not yet address is whether a Neder or a Shevu'ah that contradicts a Mitzvah can take effect at all.

The answer lies in the fundamental distinction between Neder and Shevu'ah. A Shevu'ah, which operates on the Gavra, does not take effect when it contradicts a Torah obligation, as found in the Rambam, Hilchos Shevuos 5:17, and Shulchan Aruch, Yoreh De'ah 239:4. The person is already obligated by the Torah, and thus cannot impose a Shevu'ah that negates that obligation.

A Neder, on the other hand, works through the Cheftza; it prohibits the object or act upon the person, and for that reason it can take effect even when it results in the person refraining from a Mitzvah. This distinction is brought clearly in the Mishnah in Nedarim 16a and codified in the Rambam, Hilchos Nedarim 3:7.

Accordingly, when the Gemara in Makos speaks of one who is "Bitlo," who has nullified the Aseh, it refers to someone who took an action (such as making a Neder Al Da'as Rabim) that effectively blocks fulfillment of the Aseh. Since the Neder is binding and cannot be annulled, the Aseh is considered nullified, and according to Rebbi Yochanan, this results in a liability for Malkus.

Kol Tuv,

Aharon Steiner