Question #1: The one who argues with Rav and Shmuel argues only about rice and millet. If so, this is difficult for all of them!

Question #2: Our Mishnah in Brachos (40b) is difficult for him (the one who argues with Rav and Shmuel), for there are several matters on which we bless sheha'Kol or Borei Peri ha'Adamah!

Answer: We challenge only Rav and Shmuel, for they do not consider rice and millet [to be Mazon], even though people fix a meal on them!

Inference: If so, they hold that nothing is called Mazon, except for the five grains.

However, the one who argues with [Rav and Shmuel] properly holds that everything is called Mazon, just they fixed the Brachah Borei Minei Mezonos only for matters on which people fix a meal, and people fix also on rice and millet.

Question #1 (Ri): Why did [Rav Huna] discuss a Shevu'ah in this case (when he did not say "Alai"), and a Neder in this case (when he said "Alai")? He could have distinguished in this case of a Shevu'ah itself, or a Neder itself!

When he forbade himself to eat it, he may be Me'arev with it. When he forbade himself to benefit from it, he may not be Me'arev with it!

Question #2: Below (31a), all agree that we are Me'arev only for a Mitzvah, and Mitzvos Lav Leihanos Nitnu (fulfillment of Mitzvos is not considered benefit). This implies that no Tana argues;

Below, R. Eliezer says that if he said "this loaf is Alai", we may not be Me'arev for him with it, because it is Asur b'Hana'ah. If so, he holds that we are Me'arev for Reshus, or Mitzvos Leihanos Nitnu!

Answer: The Rashbam explained that we may not be Me'arev for him with it even if he said "eating this loaf is Konam (forbidden like a Korban)", because Konam is like Hekdesh, and people will come to confuse it with Hekdesh;

However, if he said a Shevu'ah, even if he said "Shevu'ah that I will not benefit from this loaf", since people will not come to confuse it with Hekdesh, we may be Me'arev for him, for we are Me'arev only for a Mitzvah, and Mitzvos Lav Leihanos Nitnu;

[Rav Huna] mentioned "Shevu'ah that I will not eat", for even so (even though he did not forbid benefit), regarding Konam we may not be Me'arev for him.

Question: Below, when we challenge Rav Huna "[the Beraisa] should distinguish [between 'this' and 'Alai'] within the case [of a Shevu'ah]", he should answer that it means as follows. However, if he said Alai, it is as if he said "this loaf is Hekdesh", and we are not Me'arev for him with it!

Observation: According to Rashi, this is fine. We should not attribute to (say that Alai is like) Hekdesh, which is forbidden to him and to others!

Answer: We could not answer so, because [the Beraisa] concludes "because one may not be Me'arev with Hekdesh." This implies that this is only with Hekdesh, but one may be Me'arev with Konamos.

Implied question: Why can't we establish it that a Kohen has the Terumah (and Sumchus teaches that he cannot be Me'arev for a Yisrael)? Then, [the owner] cannot annul [his designation of Terumah], like it says in Nedarim (59a)!

Answer: Since [Sumchus] taught [that a Yisrael may be Me'arev] with Chulin, this implies only with Chulin, but not with Terumah, even if it is in a Yisrael's hand.

Explanation: Now we are thinking that anything due to Shevus, Chachamim did not decree about it Bein ha'Shemashos.

Implied question: Rabah, who holds [that there is an Isur Torah] of Hachanah (food preparation for Shabbos must be on a weekday), said below (38b) that Eruv takes effect at the beginning of [Shabbos], and we hold like him! (If so, what was the question?)

Answer: It is permitted to fix Tevel, for they did not decree about it Bein ha'Shemashos, until it is evident and known that it is night.

Implied question: In Shabbos (34a), a Mishnah teaches that when it is Safek dark, one may not tithe Vadai [Tevel]!

Answer: That is like Rabanan of Rebbi. Even so, one might have thought that the Mishnah here is like Rebbi, because there are many Mishnayos that the Gemara below establishes like Rebbi.

Question: If so (our Mishnah could be like Rebbi), why does [the coming] Mishnah (31a) teach "but not Tevel"? It is proper to fix it Bein ha'Shemashos!

Suggestion: That Mishnah is unlike Rebbi.

Rejection #1: We ask below (34b) "is the Reisha (32b) Rebbi, and the Seifa (34b) is Rabanan?!" We did not ask [even stronger] "is the Reisha (31a) Rabanan, and the middle clause (32b) is Rebbi, and the Seifa (34b) is Rabanan?!"

Rejection #2: We ask below (31b) "[why did the Mishnah (31a) need to teach] not with Tevel? This is obvious!" This connotes that no one disagrees.

Rebuttal (of Rejection #2): We asked "this is obvious!" because we know this from the Reisha (31a), which teaches that one may be Me'arev with Demai, which implies that one may not be Me'arev with Tevel.

Answer: Ability to fix (permit eating the Eruv) helps only for something that is permitted now to some person, e.g. Terumah, which is permitted to Kohanim.

Proof: It says above "we may not be Me'arev with Hekdesh', even though She'elah is possible (if he regrets making it Hekdesh, a Chacham can retract the Hekdesh).

Implied question: Due to Kevod Shabbos it is permitted [to tithe Lo Min ha'Mukaf, i.e. the Terumah is not near the Tevel that it exempts], like it says in Yevamos (93a)!

Answer: That is when he needs to eat the Peros on Shabbos. Here we discuss when he does not need to eat them on Shabbos.

Implied question: We are Me'arev only for a Mitzvah! (We should permit tithing Lo Min ha'Mukaf to be Machshir the Eruv for the sake of the Mitzvah, just like for Kevod Shabbos.)

Answer: They permitted tithing Lo Min ha'Mukaf only for Kevod Shabbos, but not for other Mitzvos.

Question: For the same reason, a Nazir should not be Me'arev with wine, since it is Shevus (forbidden mid'Rabanan) to permit Nedarim through She'elah on Shabbos, like we say in Shabbos (157a)!

Answer: For the need to of Shabbos, we are Sho'el, like we say there, and this (permitting Nezirus) is for the need of Shabbos, so he may drink wine on Shabbos.

Question: We should establish it also like Rabanan of Sumchus, and "everything is according to the person" refers to one who is old or sick;

Rabanan hold that we are Me'arev for an old or sick person based on the amount he eats. They are more lenient than Sumchus. They say that even something not proper for him, we are Me'arev for him, because it is proper for others. All the more so we are Me'arev with something that is proper for him, even if it is not proper for others!

Answer #1: According to Rabanan, we are not Me'arev for an old or sick person based on the amount he eats, rather, based on an average [person's] meal;

Since they do not require something proper for him, if so we are Me'arev for an old or sick person even with food that is not proper for them, only for a healthy person, and regarding food that is not proper for them, you are forced to say that the Shi'ur is like an average [person's] meal;

If so, also regarding food that is proper for them, they require the Shi'ur of an average meal, for it is unreasonable that Rabanan would have two Shi'urim for an old or sick person (dependent on whether or not the food is proper for them).

Answer #2: "Everything is according to the person" connotes that it excludes also being Me'arev for a Yisrael with Terumah.

Implied question: Why does [the Gemara] say "explain [two meals for an Eruv is according to the person himself] regarding a sick or old person"? We could likewise say that it was taught about (i.e. forbids) being Me'arev for a Yisrael with Terumah!

Answer: (Indeed, it could have.) It mentioned an old or sick person because R. Shimon ben Elazar discusses them.

Explanation: [They argue] only about when it is resting [on something on the ground while it moves], but when it is airborne, even R. Yosi b'Ribi Yehudah is Metamei, for at the time it is not considered an Ohel at all.

Source: This is like a flying bird or a Talis waving in the wind. A Mishnah (Ohalos 8:5) teaches that it does not bring or block [Tum'ah].

Support: A Beraisa brought in Nazir (55a) teaches like this. R. Yosi b'Ribi Yehudah says, if a box was full of Kelim and he threw it in Ohel ha'Mes, it is Tamei. If it was resting, it is Tahor.