NEDARIM 15 (27 Teves) - dedicated in honor of the memory of Hagaon ha'Gadol Rav Pinchas Hirschprung, well-known and much loved Rav of Montreal, Talmid of Hagaon Rav Meir Shapiro (founder of the Dafyomi study), on the day of his Yahrzeit. Dedicated by his son, Rav Yitzchak Hirschprung, may he be blessed with long years and all that he needs.

OPINIONS: The Gemara teaches that when a person makes a Neder to prohibit his eyes from sleeping indefinitely, Beis Din does not wait for him to fall asleep to give him Malkus for violating his word. Rather, Beis Din gives him Malkus immediately. This is because of the ruling of Rebbi Yochanan that a person who makes a Shevu'ah not to sleep for three days is given Malkus right away for making a Shevu'as Shav. Beis Din does not wait for him to fall asleep, since it is not possible for him to stay awake for three days.
Although one will receive Malkus for violating his Neder, is one prohibited from making such a Neder in the first place?
(a) The RAN (end of 14b) writes that there is no Isur of "Neder Shav," a Neder made in vain, as there is an Isur of Shevu'as Shav, a Shevu'ah made in vain. When the Gemara asks rhetorically, "Do we leave him [alone for several days to transgress his Neder]," it means that there is no Neder altogether. (The Gemara uses a terminology ("Do we leave him [to transgress his Neder]") which implies that there is a Neder only by way of introduction to Rebbi Yochanan's ruling with regard to Shevu'ah, where there indeed is an Isur to make such a Shevu'ah.)
(b) TOSFOS in Gitin (35a, as cited by the GILYON HA'SHAS) and the ROSH here rule that although Malkus is not administered for making a Neder Shav, one still is not allowed to make a Neder which he cannot fulfill. The verse says, "Lo Yachel Devaro" -- "he shall not profane his word" (Bamidbar 30:3). One who makes a Neder that he cannot fulfill transgresses the prohibition against profaning his word.
If, however, he transgresses the Isur of Bal Yachel, why is he not punished with Malkus? He is not punished with Malkus because his transgression is a "Lav she'Ein Bo Ma'aseh" (it involves no physical action). Although a Shevu'as Shav is also a "Lav she'Ein Bo Ma'aseh" and yet one is punished with Malkus for transgressing that Lav, this is because a special verse in the Torah teaches that Malkus is given for the "Lav she'Ein Bo Ma'aseh" of Shevu'as Shav.
The dispute between these Rishonim may depend on why Malkus is given to a person who prohibits himself from sleeping for three days. According to Tosfos, since a person cannot stay awake for three days, at the moment he obligates himself to stay awake for three days it is as if he has already transgressed the Neder. He has transgressed "Lo Yachel Devaro" since his word is considered to have been profaned since he certainly will sleep within three days.
According to the Ran, this is not the reason why the Neder does not take effect, because even though he will fall asleep within three days, he might do so b'Ones, against his will, and thus he will not be held accountable for violating the Neder. Rather, the Neder is invalid (or the Shevu'ah is a Shevu'as Shav) because the Torah does not allow a person to make a Neder or a Shevu'ah which obligates himself to do something which is not within his control. A person cannot physically keep himself awake for three days, and therefore his Neder does not take effect. The Neder is not considered a false statement or a violation of his word; rather, it merely does not take effect in the first place.
According to Tosfos, why is he considered to have violated his Neder already? Perhaps when he falls asleep, he will do so b'Ones, against his will? Perhaps Tosfos maintains that a person may not place himself in a situation in which he will be forced to transgress a Mitzvah against his will, as the RAMBAN writes in Milchamos to Shabbos (19a and 134a; see Insights there).
Alternatively, Tosfos understands that when a person says that he will not sleep and he does not specify the conditions under which he will not sleep, he means that he will sleep even b'Ones. Although it is true that he will not be punished for violating his Neder b'Ones, nevertheless when he falls asleep he profanes his word.
(Rebbi Akiva Eiger in Gilyon ha'Shas understands that the Ran (here and on 25a) disagrees with Tosfos. However, it is possible that the Ran agrees with Tosfos that one is prohibited from making a Neder which he cannot fulfill. When the Ran writes that the Torah does not prohibit one from making a Neder Shav, he means that the Torah does not include it in the prohibition against making a Shevu'as Shav (for which Malkus is given, even though it is a "Lav she'Ein Bo Ma'aseh"), but the Torah certainly prohibits it.
OPINIONS: The Gemara discusses a case in which a husband attempts to prevent his wife from visiting her father's home by prohibiting her from any benefit from him until Pesach if she visits her father's home from now until Sukos. If she receives benefit from her husband before Pesach and, before Sukos, she goes to her father's home, the benefit she received from her husband retroactively becomes forbidden and the punishment of Malkus is administered.
Who is punished with Malkus when the wife transgresses the husband's Neder -- the wife or the husband?
(a) The RAN and most other Rishonim explain that the wife is punished with Malkus for having benefit from her husband. Since he made himself prohibited to her, it is as if he is Hekdesh to her, and thus she receives Malkus like one who receives personal benefit from Hekdesh.
(b) The Ran cites the RAMBAM (Hilchos Nedarim 5:1, 5:12) who argues and rules that the only one who is punished with Malkus for the violation of a Neder is the one who made the Neder. The verse says, "Lo Yachel Devaro" -- "he shall not profane his word" (Bamidbar 30:3); there is no Isur of Bal Yachel for violating someone else's word. Hence, the person who made the Neder will receive Malkus only if he helps the other person benefit from him in violation of his Neder. (See also Insights to Nedarim 35:2.)
Nevertheless, the Rambam writes that the wife is still forbidden from benefiting from her husband, even when he does not give her the benefit. She does not receive Malkus, though, if she benefits from him.
However, if "Lo Yachel Devaro" means that one may not violate his own word and only the person who made the Neder receives Malkus, why is the other person (the "Mudar Hana'ah") prohibited from violating the Neder?
The Rambam (Hilchos Ma'achalos Asuros 9:1) rules that the Torah prohibits one from deriving any benefit from a mixture of meat and milk, but it does not prescribe a punishment of Malkus for one who does (8:16). The reason is that the Isur against deriving benefit from a mixture of meat and milk is derive from a Derashah and is not written explicitly in the Torah, and Malkus is given only for an Isur written explicitly in the Torah (MAGID MISHNEH, Hilchos Ma'achalos Asuros 5:11).
Similarly, the Rambam may understand that since the simple meaning of "Lo Yachel Devaro" prohibits only the person who made the Neder from violating his word, and the Chachamim derived from a Derashah that a Neder creates an Isur Cheftza and makes the item prohibited to the Mudar, Malkus is not given to the Mudar if he violates the Neder. The Rambam maintains that the Isur Cheftza is what prohibits the Mudar Hana'ah from benefiting from the person who made the Neder, even though the Mudar Hana'ah did not make the Neder himself. No Malkus is given, however, since the Isur is not written explicitly in the Torah but is derived through a Derashah.
The Rambam (Hilchos Shevu'os 5:4, 6:7) writes that if a person makes a Shevu'ah prohibiting another person from performing a certain action with his object, the other person must abide by the Shevu'ah. The TUR (YD 238) asks, how can a person make an Isur Gavra on another person? One can make only a Neder, an Isur Cheftza, on his object, and prohibit it to another person. The KESEF MISHNEH writes that the Rambam does not mean that the "Mushba" (the person prohibited by the Shevu'ah from doing a certain act) will receive Malkus for violating the Shevu'ah, but rather that "the Shevu'ah takes effect on him partially" with regard to making the act prohibited. (See RADVAZ on the Rambam there, TAZ to YD 236, and BACH; see also KUNTRESEI SHI'URIM 4:12 of RAV YISRAEL ZE'EV GUSTMAN zt'l.)
The Rambam's logic may be that a Shevu'ah creates not only an Isur Gavra, but it also creates an Isur Cheftza, as Tosfos writes in Shevuos (25a; see Insights to Nedarim 2:3). The Isur Cheftza, however, might not be any more severe than a normal Isur Cheftza created by a Neder, and therefore it creates only an Isur on the other person but not a Chiyuv Malkus.
The Acharonim point out that this approach may explain another ruling of the Rambam. The Rambam (Hilchos Shevu'os 2:8) rules like Rava (Shevuos 20a) that Hatfasah works for a Neder but not for a Shevu'ah. However, the Rambam (Hilchos Shevu'os 2:9) also rules that Hatfasah of a Shevu'ah does create an Isur, even though it does not create a Chiyuv Malkus (see BEIS YOSEF YD 239). Why does a Shevu'ah made with Hatfasah work to create an Isur?
The KEHILOS YAKOV (Nedarim #1) explains that the Rambam maintains that a Shevu'ah is able to create not only on Isur Gavra, but an Isur Cheftza as well. However, that Isur Cheftza is not punishable with Malkus, just like the Isur Cheftza of a Neder made on someone else. Therefore, if one is Matfis to that Isur Cheftza, he can create another Isur Cheftza which will take effect only with an Isur but not with a Chiyuv Malkus. (The Isur Cheftza is created even if he expresses the Shevu'ah in completely Shevu'ah-related terms, without referring at all to the object but only to the person.)