Three that have eaten together, it is their duty to invite [one another to say Birkat Hamazon]. One who ate demai, or first tithe whose terumah has been separated, or second tithe or sanctified property which have been redeemed, or an attendant who has eaten as much as an olive’s worth of food, or a Samaritan may be included [in the three]. But one who ate untithed produce, or first tithe whose terumah has not been separated, or second tithe or sanctified property which have not been redeemed, or an attendant who has eaten less than the quantity of an olive or a Gentile may not be counted.

Women, children and slaves they do not recite an invitation over them. How much [must one have eaten] in order for them to recite an invitation? As much as an olive. Rabbi Judah says: as much as an egg.

How do they invite [one another to recite the Birkat Hamazon]? If there are three, he [the one saying Birkat Hamazon] says, “Let us bless [Him of whose food we have eaten].” If there are three and him he says, “Bless [Him of whose food we have eaten]” If there are ten, he says, “Let us bless our God [of whose food we have eaten].” If there are ten and he says, “Bless.” It is the same whether there are ten or ten myriads (ten ten thousands). If there are a hundred he says, “Let us bless the Lord our God [of whose food we have eaten]. If there are a hundred and him he says, “Bless.” If there are a thousand he says “Let us bless the Lord our God, the God of Israel [of whose food we have eaten].” If there are a thousand and him he says “Bless.” If there are ten thousand he says, “Let us bless the Lord our God, the God of Israel, the God of hosts, who dwells among the cherubim, for the food which we have eaten.” If there are ten thousand and him he says, “Bless.” Corresponding to his blessing the others answer after him, “Blessed be the Lord our God the God of Israel, the God of hosts, who dwells among the cherubim, for the food which we have eaten.” Rabbi Yose the Galilean says: According to the number of the congregation, they bless, as it says, “In assemblies bless God, the Lord, O you who are from the fountain of Israel.” Rabbi Akiba said: What do we find in the synagogue? Whether there are many or few the he says, “Bless the Lord your God.” Rabbi Ishmael says: “Bless the Lord your God who is blessed.”

Three persons who have eaten together may not separate [to recite Birkat Hamazon]. Similarly four and similarly five. Six may separate, up until ten. And ten may not separate until there are twenty.