EXPLAINING THE MISHNAH
Question: Whom is the Tana?
It is not R. Meir, who holds that we cannot infer the positive from the negative!
Answer: It is like R. Yehudah.
Question: This is just like an earlier Mishnah (on 10b! If one said 'l'Chulin (is) what I will eat from you', he is forbidden.)
Answer #1: Since we taught about pork and idols, this was repeated.
Answer #2 (Ravina): The Mishnah means that the following are permitted like Chulin: 'like pork, idolatry...' Had it not said 'like Chulin', one might have thought that She'eilah (asking a Chacham to permit them) is required.
Objection: We would not have thought that She'eilah is required!
(Seifa): If one told his wife "you are forbidden to me like my mother," we permit it through a different Pesach.
Inference: In the Reisha, we do not require She'eilah.
Conclusion: We must rely on Answer #1; Chulin was taught needlessly.
Question: What is the source that the Nedarim in our Mishnah do not forbid?
Answer: "Ish Ki Yidor Neder" - Hatfasah must be in Davar ha'Nadur, not in Davar ha'Asur.
Question: We should expound "Le'esor Isar" to include Hatfasah in Davar ha'Asur!
Answer: That is used to teach about Isar:
(Beraisa (12a)) Question: What is Isar mentioned in the Torah? ...
VOWS OF A CHACHAM THAT DO NOT TAKE EFFECT
(Mishnah): If one told his wife "you are forbidden to me like my mother" (we permit it through a different Pesach).
Contradiction (Beraisa): If a man told his wife "you are forbidden to me like my mother", or his sister, like Orlah, or Kilayim, this has no effect.
Answer #1 (Abaye): This has no effect mid'Oraisa, but mid'Rabanan he must permit it.
Answer #2 (Rava): The Beraisa discusses a Chacham. Our Mishnah discusses an Am ha'Aretz.
Support: Also elsewhere we find that an Am ha'Aretz must permit his vow (lest he take vows lightly), but a Talmid Chacham need not:
(Beraisa): If one vowed (really, swore) b'Torah (by the Torah), it does not take effect. (He swore by the parchment. A Shevu'ah must be with Hash-m's name.)
(R. Yochanan): He must ask a Chacham to permit it.
(R. Nachman): If a Chacham swore b'Torah, he need not permit it.
(Beraisa): If one vowed (really, swore) by the Torah, it does not take effect. If he vowed by what is written in it, it takes effect. If he vowed by the Torah and what is written in it, it takes effect.
Question: If a vow by what is written in Torah takes effect, we need not teach that a vow by the Torah and what is written in it takes effect!
Answer #1 (Rav Nachman): The first two cases discuss one who holds a Sefer Torah. He refers to the names of Hash-m in it only if he said "what is written in it." In the Seifa, the Torah is on the ground. We assume that he refers to the parchment unless he says b'Torah and what is written in it.
Answer #2: In all cases the Torah is on the ground. Even so, if he says "what is written in it" the oath takes effect, and all the more so to if he says "by it and what is written in it."
Answer #3: He holds it only in the Seifa (like Answer #1). The Beraisa teaches that saying "by it" is like saying "by what is written in it."
CONCERN LEST ONE TRANSGRESS A CONDITIONAL VOW
(Mishnah): If one said "Konam that I sleep", or "that I will speak, walk, or have Bi'ah with you (my wife)", Bal Yachel applies.
(Gemara - Rav Yehudah): If a man said "Konam (an Isur is upon) my eyes to sleep today if I will sleep tomorrow", he may not sleep today, lest he sleep tomorrow;
(Rav Nachman): He may sleep today. We are not concerned lest he sleep tomorrow.
R. Yehudah agrees that if he said "Konam my eyes to sleep tomorrow if I will sleep today", he may sleep today;
He holds that a person is not careful about a Tnai (even if this causes that he transgressed his vow retroactively), but he is careful about transgressing the vow itself.