THE PROPER TEXT TO SAY
(Gemara - Shmuel): A person should never exclude himself from the assemblage (by saying "Bless" instead of "Let us bless").
Question (Mishnah): If there are three without him, [he does not say, "Let us bless" to include himself, rather,] he says "Bless"!
Answer: It means, he may say, "Bless," but it is better to say, "Let us bless."
(Rav Ada bar Ahavah - Mishnah): If there are from six people until ten, they may split up (into groups of at least three, each group will be Mezamen by itself; if there are 10, this is forbidden, for they were obligated to be Mezamen with Hash-m's name).
Question: We understand this if it is better to say, "Let us bless," for then the smaller groups can say the preferred text;
But if it is better to say, "Bless," then why may six split up? This will cause them to use the inferior text!
Conclusion: It is better to say, "Let us bless."
Support (Beraisa): Whether one said, "Bless" or "Let us bless," we do not criticize him;
Meticulous people criticize him (for excluding himself from the assemblage).
One can tell if someone is a Chacham from the way he blesses.
Rebbi says, a Chacham says (in Birkas ha'Zan), "uv'Tuvo" ( implying that Hash-m gives generously), a Bor (crude person) says, "umi'Tuvo" (connoting meagerly giving the bare essentials).
Question (Abaye): But the verse says, "umi'Birchascha Yevorach Beis Avdecha l'Olam"!
Answer (Rav Dimi): When making a request, It is proper to request a small amount.
Question: We are encouraged to make big requests -- "Harchev Picha va'Amal'ehu"!
Answer: That refers to Divrei Torah.
(Beraisa - Rebbi): A Chacham says, "b'Tuvo Chayinu," a Bor says "[b'Tuvo] Chayim" (excluding himself, as if he does not live through Hash-m's bounty).
Chachamim of Neharbal switch the opinions ("Chayim" is better, it includes all the living).
The Halachah does not follow Chachamim of Neharbal.
(R. Yochanan): A Chacham says, "Nevarech she'Achalnu mi'Shelo" (implying that all eat from His food), a Bor says, "l'Mi she'Achalnu mi'Shelo" (implying that there are different suppliers of food, i.e. he blesses his host).
Question (Rav Acha brei d'Rava): But we say (in the Hagadah on Pesach), "l'Mi she'Asah la'Avoseinu v'Lanu Es Kol ha'Nisim ha'Elu"!
Answer (Rav Ashi): There, it is clear that we refer to Hash-m, only He can do miracles.
(R. Yochanan): A Chacham says, "Baruch she'Achalnu mi'Shelo," a Bor says, "Al ha'Mazon she'Achalnu" (Rashi - he does not say that he blesses Hash-m; Tosfos - this connotes, one whom we should bless only on account of his food, i.e. the host).
(Rav Huna brei d'Rav Yehoshua): This applies only to a Zimun of three (i.e. less than ten), but if there are ten, since we say "Elokeinu," it is clear that we bless Hash-m (and saying "Al ha'Mazon" is acceptable);
(Mishnah): The others answer like the Mezamen said, "Baruch Hash-m Elokeinu... Al ha'Mazon she'Achalnu."
BERACHOS ACCORDING TO THE NUMBER OF PEOPLE
(Mishnah): The same applies if there are 10 or [up to] 10,000.
Question: The next clauses contradict this -- if there are 100, if there are 1000, if there are 10,000...!
Answer (Rav Yosef): R. Akiva equates 10 with 10,000, R. Yosi ha'Glili distinguishes them:
(Mishnah - R. Yosi ha'Glili): The Berachah is according to the number of people - "b'Makhelos Barchu Elokim..."
(Mishnah - R. Akiva): We find in synagogue...
Question: What does R. Akiva learn from R. Yosi ha'Glili's verse?
Answer (Beraisa - R. Meir) Question: What is the source that even fetuses sang Shirah at Keri'as Yam Suf? (Rashba - it was fitting for them to sing, for frightening things often cause miscarriages, but not one woman miscarried.)
Answer: "B'Makhelos Barchu Elokim Hash-m mi'Mekor Yisrael."
Question: Does R. Yosi ha'Glili have a source for this?
Answer: Yes - he learns this from "mi'Mekor" (in the Mishnah, he learns from "b'Makhelos").
(Rava): The Halachah follows R. Akiva.
Ravina and Rav Chama bar Buzi visited the Reish Galusa; Rav Chama was trying to get 100 people to bless together.
Ravina: This is unnecessary -- Rava taught that the Halachah follows R. Akiva!
(Rava): When we eat with the Reish Galusa, most of us bless in groups of three (before the Reish Galusa, and wait for him to finish and be Mezamen with the people near him).
Question: It is better to bless in groups of ten [to be Mezamen with Hash-m's name]!
Answer: If so, [they would have to bless loudly, and] the Reish Galusa would hear and he would be upset (that they blessed before him).
Question: They should wait to be Yotzei through the Reish Galusa (he will be Mezamen with Hash-m's name)!
Answer: Since there are many people, most people [are too far away and] cannot hear him.
(Rabah Tosfa'ah): If three ate together and one of them hastily blessed by himself (without a Zimun), the others can fulfill the Mitzvah of Zimun through him (if he answers); he, though, does not fulfill the Mitzvah, for it is not retroactive (after Birkas ha'Mazon).
(Mishnah - R. Yishmael): (We say "Barchu Es Hash-m ha'Mevorach.")
Rafram bar Papa visited a certain synagogue; he read in the Torah, and said only, "Barchu Es Hash-m," he did not say, "ha'Mevorach." Everyone present yelled, "Barchu Es Hash-m ha'Mevorach!"
Rava (to Rafram bar Papa): Why get involved in arguments? (Rashi - you should follow R. Yishmael, for even R. Akiva agrees that it is better to say ha'Mevorach, just he does not obligate doing so!) Also, everyone follows R. Yishmael!
WHO MAY SAY BIRKAS HA'MAZON TOGETHER
(Mishnah): If three ate together, they may not separate (and bless individually); the same applies to four or five;
If six ate together, they may separate (into two groups of three, each will be Mezamen by itself); the same applies to seven, eight or nine.
Ten may not separate (for they were obligated to be Mezamen with Hash-m's name); if there are [at least] 20, they may divide (into two groups of ten; each will be Mezamen with Hash-m's name).
If two groups ate in one house:
If they can see each other, they join for a Zimun; if not, each must be Mezamen by itself.
R. Eliezer says, we do not bless on wine until adding water (only then it is fit to drink);
Chachamim permit this.
(Gemara) Question: We already learned this (the first law of our Mishnah) in another Mishnah!
(Mishnah): If three people ate together, they must be Mezamen together!
Version #1 - Answer: Our Mishnah teaches R. Aba's law:
(R. Aba): If three sat to eat together, even if they did not eat yet, they may not separate (rather, they must eat and be Mezamen together).
Version #2 - Answer #1 (R. Aba): If three sat and ate together, even if each ate from his own loaf, they may not divide.
Answer #2: It teaches Rav Huna's law:
(Rav Huna): If three came from three groups, they may not divide (even if they did not eat together).
(Rav Chisda): This is only if each came from a group of three (and was obligated to be part of a Zimun).
(Rava): This is only if they were not party to a Zimun with the groups they left; if they were, they already fulfilled their obligation to be part of a Zimun.
Support (Rava, for himself - Mishnah): If half of a [Tamei] bed was stolen or lost, or divided among brothers or partners, it is Tahor;
If the other half was returned, it is Mekabel Tum'ah from now on.
Inference: Once it was divided, its old Tum'ah is lost;
Similarly, if those who separated from the groups were already party to a Zimun, they lost their obligation, it does not return when they come together.
(Mishnah): If two groups...
(Beraisa): If one waiter serves both of them, he makes them join.
OTHER USES OF FOODS
(Mishnah - R. Eliezer): We do not bless on wine... until adding water (only then it is fit to drink);
(Beraisa - R. Eliezer): We do not bless Borei Pri ha'Gafen on raw wine (i.e. before adding water), rather, Borei Pri ha'Etz;
Raw wine may be used to wash the hands.
After adding water, we bless Borei Pri ha'Gafen on it, and it may not be used to wash the hands.
Chachamim say, in either case we bless Borei Pri ha'Gafen, and it may not be used to wash the hands.
Question: Like whom is the following teaching of Shmuel?
(Shmuel): One may use bread for any need (Tosfos - if it is not disgraceful).
(R. Yosi b'Rebbi Chanina): Chachamim agree with R. Eliezer that we do not bless on the Kos Shel Berachah (on which we say Birkas ha'Mazon) until adding water.
Question: What is the reason?
Answer (R. Oshaya): This is the nicest way to do the Mitzvah.
Question: Why do Chachamim say that we bless Borei Pri ha'Gafen? It is not fit to drink!
Answer: (Tiferes Yisrael - it is somewhat fitting to drink raw, and also,) it is fit for Koreiti (honey and spices mixed with a majority of wine (regular mixed wine is mostly water)).
(Beraisa): There are four Halachos regarding bread (to refrain from ruining it):
We do not put raw meat over bread;
We do not pass a full cup over it;
We do not throw bread;
We do not support a bowl with bread.
Ameimar, Rav Ashi and Mar Zutra were eating together; dates and pomegranates were served. Mar Zutra threw some (cooked meat - Maharsha does not know where this belongs in the text, for it seems that he threw dates and pomegranates) in front of Rav Ashi.
Rav Ashi: A Beraisa forbids throwing food -- don't you hold like it?!
Mar Zutra: It only forbids throwing bread.
Question (Rav Ashi - Beraisa #1): Just like it is forbidden to throw bread, it is forbidden to throw [other] foods.
Counter-question - contradiction (Mar Zutra - Beraisa #2): Even though it is forbidden to throw bread, it is permitted to throw [other] foods.
Resolution: It is forbidden to throw foods that will get spoiled, it is permitted to throw foods that will not get spoiled.
(Beraisa): [For a good omen,] we stream wine out of pipes (it is caught in a vessel below) in front of a Chasan and Kalah;
We throw parched grain and nuts in front of them in summer, but not in winter (when the ground is muddy).
We may not throw rolls in summer or winter (they get ruined even in summer).
ONE WHO PUT FOOD IN HIS MOUTH WITHOUT BLESSING FIRST
(Rav Yehudah): If one put food in his mouth without blessing first, he should move it to one side and bless.
(Beraisa #1): He should swallow it.
Contradiction (Beraisa #2): He should spit it out.
Contradiction (Beraisa #3): He should move it to one side and bless.
Resolution: If the food he put in his mouth was a liquid, he should swallow it; if it is a [solid] food that will not be repulsive if he spits it out, he should do so; if it is a food that will be repulsive if he spits it out, he should move it to one side and bless.
Question: Even for a food that will not be repulsive, he should move it to one side and bless!
Answer (R. Yitzchak Kaskesa'ah): It says, "Yemalei Fi Tehilasecha" (one's mouth should be full of Hash-m's praise; one should not bless with something inside it).