QUESTION: Rebbi Avahu hosted a meal in honor of the recovery of Rebbi Zeira. Rebbi Avahu asked Rebbi Zeira to recite "ha'Motzi" on behalf of everyone. Rebbi Zeira declined, and cited the practice that the host should recite "ha'Motzi." After the meal, Rebbi Avahu asked Rebbi Zeira to recite Birkas ha'Mazon for everyone, and again Rebbi Zeira declined, and cited the practice that the one who said "ha'Motzi" should be the one to recite Birkas ha'Mazon. The Gemara explains that Rebbi Avahu was of the opinion that the guest recites Birkas ha'Mazon.

What, though, was Rebbi Avahu's reason for asking Rebbi Zeira to make ha'Motzi?

(a) The TOSFOS HA'ROSH explains that Rebbi Avahu felt that Rebbi Zeira was the host at this meal, since the meal was made on his behalf. Rebbi Zeira explained to Rebbi Avahu that the fact that the meal was made on his behalf did not afford him the status of host.

(b) The MAHARSHA explains differently. Rebbi Avahu was of the opinion that even though the host normally recites "ha'Motzi," that is only when there is no guest present who is on a higher level of scholarship. If, however, there is a guest who is greater in scholarship than the host, then that guest should recite "ha'Motzi." Rebbi Avahu felt that Rebbi Zeira was greater than he, and therefore Rebbi Zeira should recite ha'Motzi.

QUESTIONS: The Gemara asks, "Until where is Birkas ha'Zimun?" Rav Nachman and Rav Sheshes argue whether it is until "Nevarech" (Rav Nachman) or until the end of the first blessing, "ha'Zan" (Rav Sheshes). The Gemara suggests that the argument is similar to an argument between two Beraisos. One Beraisa says that Birkas ha'Mazon is sometimes "two" and sometimes "three," while another Beraisa says that Birkas ha'Mazon is sometimes "three" and sometimes "four."

What does the Gemara mean by its question, "Until where is Birkas ha'Zimun?"

In addition, what do the Beraisos mean when they say that Birkas ha'Mazon is sometimes "two" and "three," and sometimes "three" and "four"?

ANSWERS: The Rishonim present three ways of understanding these two points in the Gemara.

(a) RASHI (DH Ad Heichan) explains that the Gemara wants to know where the Zimun ends when three or more men recite Birkas ha'Mazon together. Rav Nachman says that it ends after "Nevarech." Rav Sheshes says that it ends after the first blessing. Rashi (DH d'Kasavar) points out that according to Rav Sheshes, a person who recites Birkas ha'Mazon by himself entirely skips the first blessing.

Rashi explains that when the Beraisa says that Birkas ha'Mazon is sometimes "two" and sometimes "three," it is expressing the opinion of Rav Sheshes. It means that the blessings that are mid'Oraisa are sometimes two -- when a person says Birkas ha'Mazon by himself (and omits the first blessing), and sometimes three -- when a group says it together. According to Rav Nachman, who maintains that the Zimun is only until "Nevarech" and an individual always says the first blessing, Birkas ha'Mazon is sometimes three blessings (without the blessing of the Zimun), and sometimes four (with the blessing of the Zimun).

(b) TOSFOS (DH Ad Heichan) strongly disagrees with Rashi. Tosfos says that it is unreasonable to suggest that Rav Sheshes (whose opinion is the Halachah) entirely skipped a blessing of Birkas ha'Mazon when he recited it by himself! Tosfos therefore suggests that the question of the Gemara, "Until where is Birkas ha'Zimun," refers to a case in which one person interrupted his eating in order to answer the other two who wanted to say Birkas ha'Mazon with a Zimun immediately. The Gemara wants to know if he must stop eating until after "Nevarech" or until after the end of the first blessing.

Tosfos explains that the Gemara equates the argument between Rav Nachman and Rav Sheshes to the argument between the two Beraisos. The Beraisos argue about how many people may contribute to the recitation of Birkas ha'Mazon in order to exempt everyone else. That is, if each person in the group knows only one blessing by heart, can each one recite one blessing on behalf of the others? The first Beraisa, which says that sometimes Birkas ha'Mazon is "two" and sometimes "three," means that sometimes two people may recite the three blessings (when one person knows two blessing by heart), and sometimes three people may recite the three blessings, but we may not have three people recite the three blessings and one other person recite the blessing of the Zimun. This Beraisa supports the view of Rav Sheshes, who says that Birkas ha'Zimun and Birkas ha'Zan go together and, therefore, one person must say both. However, the Beraisa that allows four people to recite the three blessings of Birkas ha'Mazon supports Rav Nachman, who says that Birkas ha'Zimun and Birkas ha'Zan are separate blessings and do not need to be recited together.

(c) TOSFOS (46b, DH l'Heichan) quotes RABEINU MOSHE of Evreux who understands that the question, "Until where is Birkas ha'Zimun," addresses a case in which one of three left the group while still eating in order to go outdoors. The other two called him to wait and join their Zimun in order to enable them to say Birkas ha'Zimun. How long must he wait before he leaves -- until the end of "Nevarech" or until the end of the first blessing, "ha'Zan"? (This explanation is very similar to the first explanation of Tosfos cited above. The only difference is that according to this explanation, the person who waited for the other two does not have to repeat the first blessing when he later says Birkas ha'Mazon, because he did not eat in the interim, while according to Tosfos' explanation the one who interrupted his meal must go back to the beginning of Birkas ha'Mazon.)