OPINIONS: The Beraisa says that in order to make a Shituf in a Mavoy, one is Mezakeh the contents of a barrel to all of the residents of the Mavoy. If the food in the barrel belongs to them (everyone owns a share in it), then he must inform them that he is making a Shituf with it. The Beraisa adds that "he must raise it up off the ground" one Tefach.

When, and why, is it necessary to raise the barrel one Tefach?

(a) RASHI (79b, DH Tzarich) proves from the Tosefta that the act of lifting the barrel is an act of being Mezakeh (an act of acquisition) for the residents of the Mavoy. The way to be Mezakeh is through Hagbahah, lifting. It is therefore necessary to lift the barrel only when the other members of the Mavoy do not yet own a portion of its contents.

(b) The GE'ONIM and the RAMBAM (Hilchos Eruvin 1:17) explain that one must lift up the barrel because the food that is used for the Shituf must be placed in a location in the Chatzer that is elevated and noticeable. Even if the contents of the barrel already belong to the residents of the Mavoy, the person who makes the Shituf must still place the barrel in an elevated area in order to make the Shituf conspicuous. They infer this from the order of the Beraisa, which states that the barrel must be lifted up after it mentions the case of the contents of a barrel that already belong to the residents of the Mavoy.

QUESTION: Shmuel rules that we may force a person to join a Shituf against his will (such as by having his wife join the Shituf on his behalf) if his obstinacy is preventing the Shituf from being made. The Gemara attempts to provide support for this ruling from a Beraisa which states that we may force a person to consent to have a Lechi or Korah erected at the entrance of a Mavoy.

The Gemara responds that the two cases are not comparable, because "in that case, there are no Mechitzos."

What does the Gemara mean? What does "no Mechitzos" have to do with forcing a person to join the Shituf or to erect a Lechi or Korah against his will?

(a) RASHI explains that without a Lechi or Korah, the Mavoy is vulnerable and exposed ("Megulah"; the Ritva's text of Rashi reads, "Megunah," or unmannerly). Therefore, we may force a person to join in erecting a Lechi or Korah in order to provide physical protection (or aesthetic enrichment, according to the Ritva's text) for the Mavoy. Shituf, however, is different, because the Mavoy has valid Mechitzos around it, and thus there is no pressing need to force him to join the Shituf.

The Rishonim question this explanation. How does a Lechi or Korah make a Mavoy less "Megulah" or "Megunah"?

(b) TOSFOS (DH Sha'ani) suggests that a Lechi or Korah enables one to carry inside the Mavoy. A Shituf Mavo'os enables one to carry from the houses and Chatzeros to the Mavoy. Without a Shituf, the residents are able to carry in the Mavoy itself, and therefore the need to make a Shituf is not as pressing as the need to erect a Lechi or Korah.

(c) The text of the Gemara according to RABEINU TAM reads that a Lechi and Korah are different because they are Mechitzos. That is, the Lechi and Korah are Mechitzos by definition, so they work even without the person's consent; whether he wants them there or not, they serve as Mechitzos. Shituf, however, requires the person's consent to give his portion of the Mavoy to the collective ownership of the Shituf (see Eruvin 49a, with regard to Eruv), and therefore a Shituf is ineffective if it is made against the will of one of the participants.

QUESTION: The Mishnah states that if the quantity of the food that comprises the Eruv became diminished, one may add to the food without informing the other residents of the Chatzer. In the end of the Mishnah, Rebbi Yosi says that the remains of the food of an Eruv ("Shiyurei Eruv") have no minimum requirement.

If any amount of leftover food from an Eruv suffices, then why does the first part of the Mishnah discuss adding to what is left? The Eruv is valid even without adding more food to what is left!

(a) The MAHARSHAL adds to the text of Rashi the words, "Rebbi Yosi argues with the Tana Kama." The Tana Kama maintains that there is a minimum amount that is required in order for the remains of an Eruv to be valid. Rebbi Yosi argues that the remains of an Eruv are valid without a minimum Shi'ur. Although these words do not appear in the early manuscripts of Rashi, the RAMBAM (Perush ha'Mishnayos) and BARTENURA explicitly write that Rebbi Yosi argues with the Tana Kama. (The wording of the Mishnah is slightly problematic according to this explanation. If Rebbi Yosi argues with the Tana Kama, then the text of the Mishnah should read "Rebbi Yosi Omer" instead of "Amar Rebbi Yosi." The latter words imply that Rebbi Yosi is adding something to the Tana Kama and is not arguing.)

(b) RABEINU YEHONASAN MI'LUNIL explains that the first part of the Mishnah is discussing a case in which the food diminished before Shabbos. An Eruv must have a minimum Shi'ur at the moment that Shabbos begins in order to be valid. Rebbi Yosi is discussing a case in which the food diminished on Shabbos, in which case it is sufficient if any of the food remains.

(This explanation of Rabeinu Yehonasan mi'Lunil is noted by the BACH (#8) on the Rif, and in his commentary to the TUR OC 368.)

(c) Alternatively, the Tana Kama does not mean that one needs to add food to the Eruv. Rather, he means that if one wants to add to the Eruv, he may do so without informing the others. Why, though, would a person want to add to the Eruv? One would want to add to the Eruv in order to ensure that if the rest of the original Eruv gets lost, the Eruv will still be valid as a result of the part that he added. (CHIDUSHEI MAHARALBACH, BACH OC 368)

(d) Rebbi Yosi says that the remains of the food of an Eruv are still a valid Eruv even when only a small bit is left, because there is already a Shituf Mavo'os, and the Eruv is made only in order that the concept of Eruvin not be forgotten (see Insights to Eruvin 46:2). Accordingly, the first part of the Mishnah might be discussing a case in which there was no Shituf, and thus the food of the Eruv does need a minimum Shi'ur. (CHIDUSHEI MAHARALBACH, MAGEN AVRAHAM)