Gemara

Rav and Rav Huna instructed their sons to try to say Birkas ha'Mazon to exempt the others.

Inference: They hold that it is better to bless than to answer Amen.

Question (Beraisa - R. Yosi): The one who answers Amen is greater than the one who blesses;

Support (R. Nehorai): We find so regarding war. The weak ones fight first, and the victory is credited to the strong ones who finish!

Answer: Rav and Rav Huna hold like the following Tana;

(Beraisa): Both the one who blesses and the one who answers Amen get reward. Reward is paid first to the one who blesses.

Chulin 87a (Beraisa): "He will spill (the blood of a Chayah or bird) and cover" - the one who slaughters covers;

R. Gamliel once obligated a man to pay 10 gold pieces for covering the blood of what another man had slaughtered.

Question: Is this for stealing the Mitzvah, or for depriving him of the Berachah?

i. This determines the fine for 'stealing' Birkas ha'Mazon (when someone else should have blessed.) It is only one Mitzvah, but it is four Berachos.

Answer: Once, Rebbi invited a Tzeduki to eat, and offered him 40 gold pieces if he will decline to [lead Birkas ha'Mazon and] drink the cup [of wine over which they bless]. The Tzeduki declined the money. A Bas Kol announced that 40 gold pieces is the value of Birkas ha'Mazon.

Rishonim

Rambam (Hilchos Brachos 1:11): Anyone who answers Amen after one who blesses is like one who blesses himself.

i. Kesef Mishneh: R. Yosi holds that one who answers Amen is greater than the one who blesses, and one Tana holds that both the one who blesses and the one who answers Amen get reward, but reward is paid first to the one who blesses. The Rambam rules like the latter Tana, for Rav and Rav Huna instructed their sons to say Birkas ha'Mazon to exempt the others, i.e. for it is better to bless than to answer Amen. We do not find Amora'im who hold like R. Yosi.

Levush (OC 215:2): One who answers Amen is greater, for he strengthens and affirms that what the Mevarech said is true.

Rosh (Chulin 6:8): A case occurred in which Reuven told Shimon "circumcise my son", and Levi did it. Shimon claimed the fine of 10 gold pieces from Levi, and R. Tam exempted him, for nowadays we do not collect in Chutz la'Aretz matters without monetary loss. Even if Shimon seized it, we return it to Levi, since he was there at the time of the Milah and answered Amen, and one who answers Amen is greater than one who blesses. If he heard and did not answer, he caused his own loss. Regarding Kri'as ha'Torah, if one got up to read and the Gabai had not called him, even in Eretz Yisrael (where judges with Semichah collect fines) he would be exempt, for all are obligated in Kri'as ha'Torah, and the Gabai calls people merely to avoid fights. Even if a Yisrael got up and read in place of the Kohen, we do not obligate him.

Ma'adanei Yom Tov (4): Why does the Rosh rule like R. Yosi? Presumably, the Halachah follows Rav and Rav Huna, who hold like the Tana who disagrees! It seems that it is because R. Nehorai gave a proper support for R. Yosi, and [we often follow R. Yosi against a Rabim because] Nimuko Imo. Therefore, it seems that the Beraisa that supports Rav and Rav Huna does not argue with R. Yosi, who says that the one who answers Amen is greater. Rather, both of them are true. The one who answers is greater, for he is victorious and completes the matter. However, just like the Mevarech [blessed] before the Oneh [answered], so they give to him his reward first. Rav and Rav Huna were concerned for their children to be rewarded quickly. They were not concerned for the bigger reward. This also explains why Rebbi wanted to give to 40 gold pieces to [the Tzeduki. The Tzeduki] can answer Amen (he gains if someone else blesses)! Rather, everyone (i.e. most people) are more adamant about Brachos to get reward quickly than to get a bigger reward. It seems that Rashi disagrees and holds that Tana'im argue [and presumably, we hold that the one who answers is greater].

Rosh (Brachos 7:27): When Rava ate with the Reish Galusa, they used to bless in groups of three. If they would bless in groups of 10, the Reish Galusa would hear and he would be upset. Even though they were obligated to bless with 10, it is better [to bless in groups of three] than not to be Yotzei Birkas ha'Mazon.

Rosh (Teshuvah 4:19): I say Yotzer Ohr and Ma'ariv Aravim quietly with the Shali'ach Tzibur, for one cannot always intend to hear from the Shali'ach Tzibur while listening silently. And even if he intends, if in the middle his mind diverted to other matters, he was not Yotzei. If he himself said it, he was Yotzei even in such a case. At the end of the Brachah I am quick to finish before the Shali'ach Tzibur finishes, and I answer Amen.

Gra (OC 59:1): He connotes that most people were silent and were Yotzei through the Shali'ach Tzibur. The Rosh said it quietly, for the primary Mitzvah is to hear from the Shali'ach Tzibur.

Poskim

Shulchan Aruch (OC 59:4): One says Birkas Yotzer Ohr and Ma'ariv Aravim quietly with the Shali'ach Tzibur.

Beis Yosef: Our custom is unlike the Rosh. We say the entire Brachah word for word with the Shali'ach Tzibur, and then one may not answer, for it is like answering to his own Brachah. We learn from Maharik and Ramah that one need not answer Amen.

Rema: He should finish quickly before the Shali'ach Tzibur finishes, and answer Amen after the Shali'ach Tzibur. However, if he did not say it, just he heard from the Shali'ach Tzibur, he was Yotzei.

Mishnah Berurah (18): He likewise answers Amen if he heard from someone else. The same applies to this Brachah and other Brachos.

Shulchan Aruch (183:6): The Mesubin (those who ate) ... must hear and understand what the Mevarech says.

Shulchan Aruch (7): It is proper that all the Mesubin say quietly with the Mevarech every Brachah, including the closing.

Mishnah Berurah (28): The Tashbatz says that until ha'Zan Es ha'Kol, everyone must be silent and hear and intend to be Yotzei through the Mevarech. Afterwards they bless by themselves with the Mevarech. This is not our custom, but when one knows that the Mesubin hear and intend to be Yotzei, and understand Leshon ha'Kodesh, it is proper to do like Tashbatz.

Rema: He should finish slightly before the Mevarech, so he can answer Amen, like above (59:4).

Kaf ha'Chayim (37): Chesed l'Avraham says that the custom of Sefardim, that all the Mesubin bless Birkas ha'Mazon, is good. The custom in some places in Ashkenaz, that they rely on the Mevarech, is not good. The Mekubalim say that through the Brachah, one clarifies sparks of Kedushah in the food. Everyone must do so according to his level. It is not proper to rely on others when he himself can bless.

Shulchan Aruch (193:1): If 10 ate together, they may not divide into groups of three, for they must be Mezamen with Hash-m's name. However, if in a large group people cannot hear the Mezamen, and they cannot separate into groups of 10 lest the Ba'al ha'Bayis hear and be upset, they may separate into groups of three and be Mezamen quietly, so the Ba'al ha'Bayis will not hear. This is better, for if they do not hear the Mezamen, they are not Yotzei the obligation of Birkas ha'Zimun.

Beis Yosef: The Rosh and Tur said "if they do not hear, they are not Yotzei Birkas ha'Mazon." It seems that they mean that if they do not hear the Zimun, they are not Yotzei Birkas ha'Zimun. If they do not hear Birkas ha'Mazon, they could bless for themselves! It is good for everyone to bless for himself, like I wrote above (183).

Rebuttal (Darchei Moshe 3): When there is a Zimun, everyone can bless quietly himself and also answer Amen to every Brachah. One loses [answering Amen] when he blesses alone. L'Chatchilah, one must hear all of the Brachos from the Mevarech and answer Amen, even though he said it quietly himself, like I explained above (59:3).

Bach (5): Even though Shibolei ha'Leket citing R. Avigdor and Orchos Chayim citing R. Peretz said [like the Beis Yosef], Tosfos, the Rosh and the Tur disagree. Maharam would not bless quietly, for l'Chatchilah three must join for all of the Brachos. We learn from "Ki Shem Hash-m Ekra Havu Godel lei'Lokeinu." If one blesses quietly, he cannot answer Amen. Even though he can finish earlier and answer, there is concern lest he not [finish in time to] be able to answer. Birkos Kri'as Shma is different. There, since everyone may bless for himself, he is not obligated to answer Amen. When there is a Zimun, one does not say with the Mezamen, for he must hear the Brachah and answer Amen.

Perishah (5): Even though in groups of three they hear the Zimun, they do not hear all of Birkas ha'Mazon, for normally one's voice lowers the longer he speaks. The Rosh used to say Birkos Kri'as Shma quietly, and answer Amen to the Shali'ach Tzibur. We should do so also for Birkas ha'Mazon, and fulfill "one who answers Amen is greater than the one who blesses..." However, since the Rosh said "if not, he was not Yotzei" connotes that he refers to Birkas ha'Mazon.

Taz (3): Seemingly, even though they can choose to divide, it is better not to divide, for b'Rav Am Hadras Melech, like the Rema says in Sa'if 2. However, if so the Tana should have taught this! Beis Shamai would agree to Beis Hillel that one must bless [on fire on Motza'ei Shabbos] for everyone, due to b'Rav Am, if not for Bitul Torah (Brachos 53a). Why can they choose here? And why didn't the Rema say here that it is better not to divide? Only here they may choose to divide, for then everyone is part of a Zimun and there is some fulfillment of b'Rav Am, and there is also the attribute of dividing Brachos. If all bless together, b'Rav Am is fulfilled better. These attributes are equal. The Bach said in the name of the Rema that also when there are 20, it is better not to divide; I disagree.

Magen Avraham (4): The Mechaber holds that it suffices to hear the Zimun, and bless the rest by himself. Above (183), Darchei Moshe wrote that it is better to hear all of the Brachos from the Mevarech and answer Amen, like regarding Kri'as Shma. Below (195:3), why did the Rema agree with the Mechaber? I say to follow Darchei Moshe. If one will not be able to hear all of Birkas ha'Mazon, they should be Mezamen in groups of three.

Shulchan Aruch (195:3): Whenever two groups join, both of them must hear Birkas ha'Zimun clearly from the Mevarech.

Rema: The rest of Birkas ha'Mazon, everyone blesses by himself. If they want, the Mezamen can be Motzi all of them if they hear all of Birkas ha'Mazon.

Mishnah Berurah (10): The Mechaber holds that Birkas ha'Zimun is Nevarech and Baruch she'Achalnu. The Rema holds that it is until ha'Zan Es ha'Kol, but l'Chatchilah it is better to hear all of Birkas ha'Mazon from the Mevarech and be Yotzei through him.

Shulchan Aruch (201:6): One must strive that they should give to him the cup to bless (lead Birkas ha'Mazon).

Magen Avraham (6): Rashi explained that the one who blesses is rewarded first. However, both of them receive the same reward. It seems that the Tur agrees. However, in YD (28), [the Tur] rules that the one who answers Amen is greater! We must say that it is a comment not from the Tur, like the Beis Yosef said there. In CM 382, the Rema rules like this regarding Milah (one who answers is greater)! It seems that the law is true (Machatzis ha'Shekel - the Rema holds like Rashi). One who answers gets reward like the Mevarech. Even though the Mevarech is rewarded first, one who stole a Mitzvah need not pay to compensate for this.

Kaf ha'Chayim (28), and Eliyahu Zuta (124:4) citing the Shlah: Even the one who holds that one who answers Amen is greater, one who blesses with awesome Kavanah is greater than one who answers.

She'elas Rav (ha'Gaon R. C. Kanievsky Shlita, 2:20:9): It is better to bless ha'Gomel himself than to be Yotzei through hearing it.

Shulchan Aruch (284:3): One must intend for the Brachos of those who read from the Torah and the Haftorah and answer Amen, and they count towards 100 Brachos.

R. Akiva Eiger: Even though one who hears is like one who says, here it is inferior because he did not read from the Torah. Only if he answers Amen, which is greater [than one who blesses], it counts towards 100 Brachos, like Mishbetzos Zahav (124:4) said [about answering to Chazaras ha'Shatz].

Shulchan Aruch (CM 382:1): If Reuven had a son to circumcise, and Levi did it, he must pay him 10 gold pieces. However, if Reuven asked Shimon to circumcise, and Levi circumcised, he is exempt.

Beis Yosef (DH v'Chosvu): Tosfos (Chulin 91b DH vChaivo) cites a case in which a Shali'ach Tzibur called Ploni to read the Torah, and Almoni came first and read. R. Tam exempted him, for Ploni was able to answer Amen; one who answers Amen is greater than one who blesses.

SMA (7): This exemption is only for Mitzvos for which it was enacted to bless aloud in a Tzibur, e.g. for Bris Milah. Then, surely Reuven heard the Berachah. We do not say so about Shechitah. Milah is incumbent on the father, therefore if another circumcised, he must pay 10 gold pieces even if the father answered Amen.

Rebuttal (Shach 4): The source to exempt due to Amen is from R. Yerucham. He exempts even for Milah! R. Gamliel obligated one who blessed quietly.

SMA (7): Even though Reuven was able to answer Amen, this does not exempt Levi because the Mitzvah is special for Reuven more than for others.

Yam Shel Shlomo (Chulin 8:60): It is difficult to say that we discuss a Rasha who denied Reuven the chance to answer Amen. I say that answering Amen does not exempt. One who answers is greater than one who just blesses, e.g. Tefilah or Kri'as ha'Torah. Regarding covering the blood or Milah, which is a Mitzvah by itself even without the Berachah, he pays for the Mitzvah itself. If one seized the fine, he need not return it even if he answered Amen.

Rebuttal (Shach 4): The Gemara concluded that the 10 gold pieces are primarily for the Berachah. Shimon was not a Rasha. He merely blessed quietly!