Gemara

(Mishnah - R. Eliezer): If Reuven was Makdish property Meshubad to pay his wife's Kesuvah, when he divorces her, he must vow not to benefit from her (lest he schemes to remarry her after she collects from Hekdesh);

R. Yehoshua says, he need not vow.

Suggestion: They argue about a Neder b'Rabim (made in front of many people).

R. Yehoshua holds that it can be permitted, so it is useless to force the husband to vow. (He will permit his vow later);

R. Eliezer holds that it cannot be permitted.

Objection: If so, why does R. Yehoshua say that he need not vow? He should say it would not help to vow!

Bechoros 45b (Mishnah): If a Kohen married a woman forbidden to him, he is Pasul until he vows not to benefit from her.

Question: We should be concerned lest he go to a Chacham to permit his vow!

Answer: Our Tana holds that one must be Mefaret (tell all details of) a vow before a Chacham may permit it.

Gitin 35b (Rav Huna): R. Gamliel enacted that a widow vow (that she did not receive anything from her Kesuvah before collecting it from the orphans), i.e. before she remarried. If she already remarried, she does not vow.

Question: Surely, this is because her husband will annul the vow. Also before she remarries, perhaps she will vow falsely, and go to Beis Din to permit it!

Answer: He holds that one must be Mefaret a vow in order to permit it.

(Rav Nachman): One need not be Mefaret a vow in order to permit it.

If he needed to, sometimes he would omit a detail, and the Heter (permission) would be invalid, since Beis Din permits only what they hear!

(Rav Papa): He must be Mefaret the vow.

We are concerned lest he seeks to permit a vow in order to transgress!

Nedarim 65a (Beraisa): If Reuven vowed not to benefit from Shimon, he may annul his vow only in front of Shimon.

(Rav Nachman): We learn from "Hash-m said to Moshe in Midyan 'go return to Mitzrayim, for all the men have died'". Since Moshe vowed in Midyan (to Yisro), he needed to go to Midyan to annul his vow (in front of him).

"He (Tzidkiyahu) also rebelled against Nebuchadnetzar, who made him swear by Hash-m's name." He had seen Nebuchadnetzar eat a live hare. Nebuchadnetzar made him swear not to reveal this. Tzidkiyahu permitted his oath and revealed the matter.

Nebuchadnetzar summoned the Sanhedrin and Tzidkiyahu.

Nebuchadnetzar: May one permit an oath not in front of the one to whom he swore?

The Sanhedrin: No.

Nebuchadnetzar: Why did you annul his oath when I was not there?!

Rishonim

Perush ha'Mishnayos (Bechoros 45b): If a Kohen vowed benefit from his wife (who is forbidden to him), he cannot permit the vow, for we hold that one must detail the vow.

Rosh (10): Rav Huna holds that one must detail the vow to permit it. If he did not, even b'Di'eved it is not permitted. The Halachah follows Rav Papa, who obligates detailing, for he is Basra. Also, Rav Huna supports him, and the Yerushalmi connotes that this is the Halachah.

Ran (Gitin 18b DH DH v'Kaima): We hold that one must be Mefaret, even though Amora'im argue about this. This is clear from the Yerushalmi. A man came in front of R. Yudan to permit a Neder that he will not profit. R. Yudan questioned this, and the Noder explained that he vowed not to profit from dice-playing. R. Yudan said 'Blessed is He who chose them (Chachamim), who said that one must be Mefaret.'

Ran (Nedarim 65a DH v'Heicha) and Rosh (Nedarim 9:2): One must permit an oath not to benefit from Shimon in front of Shimon, only if was for Shimon's benefit. Then, Shimon's consent is required. R. Tam says so. If they permitted him without his consent, it seems from Gitin that b'Di'eved it is permitted. It asked that perhaps a widow will go to Beis Din to permit a vow to orphans. If it is not permitted b'Di'eved, what is the concern? She vowed for their benefit! Also, the Sanhedrin permitted Tzidkiyahu's vow that he made for Nebuchadnetzar's in the latter's absence!

Ran (ibid.): Tosfos says like this. The Ra'avad and others reject these proofs. Even b'Di'eved it is not permitted. The verse says that Tzidkiyahu rebelled against Nebuchadnetzar. He and the Sanhedrin were punished for this. Gitin is not a proof. Once she vowed to the orphans, they do not gain if Peros are forbidden to her. Also, perhaps she will think that she is permitted (but really, she is not).

Tosfos (23a DH Mar): Why are we concerned lest a vow b'Rabim be permitted? Since one must be Mefaret, the Chacham will not permit it! We can say that one must detail only the text of the vow, but not why he vowed. This is unlike the case in which a Kohen who married a divorcee vows and serves. There, he vows 'not to benefit from my forbidden wife.'

Rashba (Teshuvah 4:62): We hold that one must detail a vow in order to permit it. We learn from Gitin that one must give the reason for it. We require detailing primarily so that they will not permit a vow to distance from an Aveirah or theft. Presumably, it suffices to detail it to one of the three judges who permit. If he was an expert, he could permit it himself. Even though there are three judges, we do not suspect that even one of them would permit if he knew that it depends on an Isur. I see no difference between an expert and a commoner. It is not a Gezeras ha'Kasuv to detail in front of three. It is a mere concern mid'Rabanan. If even one of the judges knows, this removes the concern, especially if that judge explains to the others in the name of the Noder. This is no worse than a translator. One may permit through a translator, like the Yerushalmi (10:8) says.

Rivash (395): We hold like Rav Sheshes, that dice-playing is not even an Isur mid'Rabanan. One who does so (for his occupation) is Pasul for testimony only because he does not contribute to society. Even so, R. Yudan refused to permit his vow, for it is repulsive to permit frivolity. If R. Yudan holds like Rav Sheshes, this shows that we do not permit even when there is not even an Isur mid'Rabanan. If he wanted to sanctify himself and make a fence to abandon his evil way, and now wants to follow his lusts, why should we permit him? The Ramban says so to explain why we do not permit a Cherem of the Tzibur.

Poskim

Shulchan Aruch (YD 228:14): Before we permit a vow, the Noder must detail the vow and the reason he vowed. If he did not detail it, it is not permitted. However, it suffices to detail it to one of the judges who permit.

Beis Yosef (DH Tzarich): Tosfos, the Rashba, the Ran and Mordechai learn from the Yerushalmi that one must be Mefaret. It connotes that it is not enough to detail the (words of the) vow. Rather, one must also explain his intent. Rashi says that one must explain how (why) he vowed. The Chacham will hear that it was in order to collect from orphans, and he will not permit it. The Rashba says that this is the primary reason for detailing the vow.

Beis Yosef (YD 228 DH Kasav ha'Rivash): The Rivash proved that we do not permit a vow even for an Isur mid'Rabanan. The Rosh, Rashba and Rivash say that if one did not detail the vow, even b'Di'eved it is not permitted. The Radach says that if the judges did not know that he vowed Al Da'as another person, and they permitted, perhaps it is permitted. The Rivash (370) disagrees.

Taz (19): Rashi explains that we are concerned lest a widow vowed to orphans "all Peros are forbidden to me if I benefited from my Kesuvah." If she could say 'I forbade all Peros to myself' and permit it without specifying, a Michshol (transgression) would result. If she says the entire vow, a Chacham would not permit her. The Gemara gave another reason, lest he vowed about an Isur, i.e. to forbid all Peros to himself if he transgresses an Isur that he often transgresses. The Yerushalmi gives another reason, i.e. the case of the dice-player. We are concerned that no detail of the vow, e.g. a Tanai, be omitted. Also, the exact text must be said, lest he use a different expression (I will not profit) to disguise the content of the vow. Tosfos says just like I said. The Gemara proves that this is correct.

Prishah (22, cited in Shach 25): The Beis Yosef brings from Rashi and the Rashba that one must detail also the reason why he vowed. The Shulchan Aruch rules like this. Why aren't even meticulous Chachamim careful about this?! The Gemara and Poskim do not mention detailing the reason. Also, we can distinguish. Chachamim required detailing the reason only for a bizarre vow, such as 'I will not profit.' For a normal vow, we are not concerned lest it was about an Isur. However, Rashi and the Rashba wrote Stam (that one must detail the reason), and their proof is solid. One may not veer from their words, especially since the Beis Yosef and Rema ruled Stam like them. Most vows that people seek to permit are to fast or abstain from meat and wine, to afflict oneself. The Noder wanted to improve himself, so we do not ask the reason. When he vowed about other matters, e.g. not to give benefit to someone else, the Chacham must know the reason.

Rebuttal #1 (Shach 25): The Gemara and Poskim explicitly obligate detailing the vow, i.e. the reason for it. This is clear from Gitin and Bechoros. The Prishah's answer does not explain why the custom is that we never explain the reason for the vow. Also, according to the Prishah, all the more so one must detail the reason, lest we think that he intended to improve himself, and this is wrong! The Gemara and Poskim connotes that one must always detail it. However, it is the Noder's obligation to detail it. The Chacham need not ask him. If one does not give the reason, it is because he vowed Stam, without a reason. If one vowed for a reason and does not explain it, this is his transgression. We do not bring a proof from fools.

Rebuttal #2 (Taz): They (Rashi, the Rashba, Beis Yosef and Rema) intended only to prevent omission of Tanayim of the vow or switching the words, but if the Noder said the exact text, we need not ask what was in his heart at the time, for any vow. No Michshol will come even if we do not know the reason, since he did not explicitly make the vow contingent on anything.

Gra (24): The Ran and Rosh say that if he did not detail the vow, b'Di'eved it is not permitted. One could reject the proof from Gitin. We are not concerned because l'Chatchilah, a Chacham permits only if the vow was detailed. According to the opinion that one need not detail a vow, a Chacham would permit l'Chatchilah. The Rashba's proof (35b DH Ibo'i) is solid. Rav Nachman is concerned lest one omit a word. (I.e. the one who requires detailing holds that if a word was omitted, even b'Di'eved it is not permitted.)