and he returned to the beginning of Grace after Meals and repeated it. Giddel bar Manyumi said to Rav Naḥman: Why did the master act in that manner? He said: As Rabbi Sheila said that Rav said: If one erred, he returns to the beginning.

Giddel bar Manyumi challenged: Didn’t Rav Huna say that Rav said: If one erred, he recites: Blessed…Who gave? Rav Naḥman said to him: Wasn’t it stated about this that Rabbi Menashya bar Taḥlifa said that Rav said: They only taught that one recites the short blessing in a case where he did not yet begin reciting: Who is good and does good; however, if he already began reciting: Who is good and does good, he must return to the beginning of Grace after Meals?

Rav Idi bar Avin said that Rav Amram said that Rav Naḥman said that Shmuel said: If one erred and did not mention the formula for the New Moon in his Amida prayer, we require him to return to the beginning of the prayer and repeat it. However, if one erred and forgot to mention the New Moon in Grace after Meals, we do not require him to return to the beginning and repeat it.

Rav Avin said to Rav Amram about this: What is the difference between the Amida prayer and Grace after Meals? He said to him: That question was also difficult for me and I asked Rav Naḥman about it, and he said to me: I did not hear the reason from Mar Shmuel himself, but let us see if we can analyze it ourselves. For the Amida prayer, which is an obligation, we require him to return to the beginning of the prayer and repeat it. For Grace after Meals, which is not an obligation, as if he wants to eat, he eats and if he wants not to eat, he does not eat, we do not require him to return to the beginning and repeat it. Grace after Meals is not a full-fledged obligation; it is dependent upon eating, which is optional. Consequently, failure to mention the New Moon in Grace after Meals is not a source of concern.

The Gemara asks: If so, on Shabbatot and Festivals, when there is a mitzva to eat and when it is not possible to refrain from eating, there too, if he erred and failed to mention them in Grace after Meals, would you say that he must return to the beginning and repeat it? He said: Yes. As Rabbi Sheila said that Rav said: If one erred, he returns to the beginning of Grace after Meals. The Gemara asks: Didn’t Rav Huna say that Rav said: If one erred, he recites: Blessed…Who gave? The Gemara rejects this: Wasn’t it stated about this: They only taught that one recites the short blessing in a case where he did not yet begin reciting: Who is good and does good; however, if he already began reciting: Who is good and does good, he must return to the beginning of Grace after Meals.

There is a dispute in the mishna: How much must one eat to obligate those with whom they ate in a zimmun? An olive-bulk; Rabbi Yehuda says: An egg-bulk.

The Gemara asks: Is that to say that Rabbi Meir considers an olive-bulk significant and Rabbi Yehuda considers an egg-bulk significant? Didn’t we hear them say the opposite elsewhere? As we learned in a mishna: And similarly, one who left Jerusalem and remembered that there was consecrated meat in his hand, which may not be removed from Jerusalem, if he passed Mount Scopus, or anywhere that is a comparable distance from the Temple Mount, he burns the sanctified meat at the site where he is located; and if he has not yet traveled that distance, he must return to burn it before the Temple with the wood of the arrangement that was designated for burning consecrated items that were disqualified.

The mishna continues: How much meat must be in their possession in order to obligate them to return? Rabbi Meir says: One must return for an egg-bulk of this, sanctified meat, and that, leaven mentioned there previously. And Rabbi Yehuda says: One must return for an olive-bulk of this and that. Their opinions there seem to contradict their opinions in our mishna.

To resolve this contradiction, Rabbi Yoḥanan said: The opinions are reversed in one of these sources and must be emended. Abaye said: Actually do not reverse them. Here, with regard to zimmun, they disagree with regard to the interpretation of verses. Rabbi Meir holds: “And you shall eat,” that is eating; “and be satisfied,” that is drinking after eating. The halakha is in accordance with the standard halakhic principle that eating is defined as the consumption of an olive-bulk. And Rabbi Yehuda holds: “And you shall eat and be satisfied,” refers to eating that includes satisfaction. And what is considered eating with satisfaction? The consumption of an egg-bulk.

On the other hand, there, in the case of leaven and sanctified foods, they disagree not with regard to the interpretation of verses, but with regard to logical reasoning. Rabbi Meir holds: The requirement to return consecrated food is analogous to its ritual impurity, and just as its susceptibility to ritual impurity is only when it is the size of an egg-bulk, so too, the requirement to return it is only when it is the size of an egg-bulk. And Rabbi Yehuda holds: The requirement to return consecrated food is analogous to its prohibition, and just as its prohibition is only when it is the size of an olive-bulk, so too, the requirement to return it is only when it is the size of an olive-bulk.

MISHNA: The mishna delineates distinctions in the halakhot of the zimmun blessing, based on the number of people present. How does one recite the zimmun? In a group of three people, the one reciting the zimmun says: Let us bless the One from Whose food we have eaten. In a group of three people and him, the one reciting the zimmun says: Bless the One from Whose food we have eaten, as even without him there are enough people to recite the zimmun.

With the increase in the number of participants, the blessing is more complex. In a group of ten people, the one reciting the zimmun says: Let us bless our God. In a group of ten people and him, the one reciting the zimmun says: Bless our God. This formula is recited both in a group of ten and in a group of one hundred thousand.

In a group of one hundred people, the one reciting the zimmun says: Let us bless the Lord our God. In a group of one hundred people and him, the one reciting the zimmun says: Bless the Lord our God. In a group of one thousand people, the one reciting the zimmun says: Let us bless the Lord our God, the God of Israel. In a group of one thousand people and him, he says: Bless the Lord our God, the God of Israel. In a group of ten thousand people, the one reciting the zimmun says: Let us bless the Lord our God, the God of Israel, the God of Hosts, Who sits upon the cherubs, for the food that we have eaten. In a group of ten thousand people and him, the one reciting the zimmun says: Bless the Lord our God, the God of Israel, the God of Hosts, Who sits upon the cherubs, for the food that we have eaten.

The principle is that just as he recites the blessing, so too those present recite in response: Blessed be the Lord our God, the God of Israel, the God of Hosts, Who sits upon the cherubs, for the food that we have eaten.

On a similar note, Rabbi Yosei HaGelili says: According to the size of the crowd, they recite the blessing, as it is stated: “Bless you God in full assemblies, even the Lord, you who are from the fountain of Israel” (Psalms 68:27). Rabbi Akiva said that there are no distinctions based on the size of the crowd: What do we find in the synagogue? Both when there are many and when there are few, as long as there is a quorum of ten, the prayer leader says: Bless [barekhu] the Lord. Rabbi Yishmael said that in the synagogue, one recites: Bless the Lord the blessed One.

GEMARA: Shmuel said: One should never exclude himself from the collective.

The Gemara raises a challenge from what we learned in our mishna: In a group of three people and him, the one reciting the zimmun says: Bless the One from Whose food we have eaten. He thereby excludes himself from the collective.

The Gemara answers: Say that the meaning of the mishna is: