פירוש על ברכות 8:8

מברך על היין ואחר כך מברך על המזון – Since [the recitation of] ברכת המזון/The Blessing after the Meal does not require a cup [of wine]. But the School of Hillel holds that ברכת המזון requires a cup.

Introduction The final mishnah of our chapter contains one more debate between Bet Shammai and Bet Hillel.

עונין אמן אחר ישראל המברך – And even though he did not hear the mention of The (God’s) Name other than at the end of the blessing, since it is assumed that towards Heaven, he recited a blessing.

If wine comes to them after the food, and there is only that cup: Bet Shammai says: he blesses over the wine and then he blesses over the food; But Bet Hillel says: he blesses over the food and then he blesses over the wine. Bet Hillel’s position is more familiar so I will begin with it. Bet Hillel holds that if there is only one cup of wine left over at the end of the meal he should recite the Birkat Hamazon and then drink the wine and then bless over it. This way the Birkat Hamazon is recited over the cup of wine. Many Jews still do this at every Shabbat meal and it is most traditional at the seder, at weddings and at circumcisions. Bet Shammai says that he may drink the wine first and that he does not need to recite the Birkat Hamazon over a cup of wine. Alternatively Bet Shammai may hold that reciting Birkat Hamazon over a cup of wine means that he first drinks the wine and then recites Birkat Hamazon.

אלא אם כן שמע כל הברכה – lest he (i.e., the Cuthean) recited a blessing towards Mount Gerizim.

They answer amen after a blessing said by an Israelite but they do not answer amen after a blessing said by a Samaritan, until he hears the whole blessing. One answers amen to blessings recited by other Israelites but not to blessings recited by Samaritans unless one is sure that the blessing was recited properly. The concern is that the Samaritan may have recited an idolatrous blessing. Samaritans were originally an Israelite group but had long since separated themselves from the more mainstream Jews. Hence, in some matters they were considered Jewish while in others they were considered to be Gentiles. In our case they cannot assumed to be acting like Jews and reciting proper blessings unless it can be proven.