This Halacha is an excerpt from our Sefer
Obligation to answer Amen:
A. The greatness and the obligation:
See Yesod Veshoresh Havoda 5:6 [page 110 in file] It is an obligation to answer Amen towards the blessing said by a Jew. This applies even if the person who hears the blessing is not obligated in this blessing at all.
The meaning: The word Amen is an acronym for the words Keil Melech Neman, [which means that Hashem is a trustworthy king and will fulfill the blessing]. Amen is an expression of belief coming from the word Hamanas Devarim [i.e. Emuna].
The intent required when asnwering Amen: The intent that one is to have in mind upon answering Amen is that the blessing that the person said is true and I believe in this. This intent however is only applicable by those blessings that are factual statements of Hashem’s greatness [such as Baruch Sheamar, Yishtabach, and Goal Yisrael]. However, those statements that are a request and appeal towards Hashem, such as the stanzas of Kaddish [which is a request that Hashem return his Shechina] and the like, one is to intend on the future, that the words will come true and his request will be speedily fulfilled. By those statements that are both admiration and praise and also hope and anticipation that the words being said will be speedily fulfilled, it is proper to intend in the Amen both interpretations; that the statement said is true and that his words will come true and it will be speedily fulfilled. An example of such blessings are the middle blessings of Chazaras Hashatz, as well as the blessings of Ritzei and Sim Shalom.
Amen to a blessing that does not include Hashem’s name: Whoever blesses another Jew it is a Mitzvah to answer Amen to his blessing. [This applies even though Hashem’s name is not mentioned in the blessing, such as by a Mi Shebeirach, or Harachaman, or a personal blessing given by a friend and the like. An example of this would be for a mourner to answer Amen towards a comforter parting remarks of consolement. One is however not to answer Amen to a blessing that is said without Hashem’s name because of a doubt, such as the blessing of Baruch Patrani Meonsho Shel Zeh.]
One who hears a blessing and does not answer Amen, his punishment is very great.
The greatness-Answering Amen is in one aspect even greater than saying the blessing:
Whoever answers Amen is [in one aspect] even greater than the person who said the blessing. Accordingly, we rule that whoever stole a Mitzvah and its blessing from another, a fine is not given if the “owner” was able to answer Amen. On the other hand, regarding another aspect, the person who says the blessing is greater than the person who says Amen. Thus, the reward of one who says the blessing and one who answers Amen is equal. Nevertheless, Hashem hastens the reward of one who says the blessing more than one who answers Amen. Accordingly, we rule that if a person has the choice between saying the blessing or answering Amen he should choose to say the blessing.
The reasons for its greatness: The reason Amen holds an advantage over the blessing is because the Amen is the finalization of the blessing, and is similar to the last warrior who won the battle. The Amen helps make the blessing become effective and draw down its Divine request. The Amen destroys any prosecuting angels who prevent the blessing from becoming true. It also banishes the forces of evil from nurturing from the blessing. A blessing is similar to an unnotarized document, and the Amen is like a notary to the blessing that it will take place. The Amen is the second witness, who joins the first witness which is the person saying the blessing, to authenticate the blessing. Alternatively, the reason is because one who hears a blessing is as if he said it, and since in addition he answers Amen, he is therefore greater than the person who said the blessing who may not say Amen. Alternatively, the reason is because in the word Amen is hinted two names of Hashem, both Adnai and Havayah. Alternatively, the reason is because answering Amen includes three Mitzvos: Shavua, Kabala and Emuna.
Rav Mordechai Jaffe, the author of the Levushim, once visited his teacher Rabbi Abuhav to study from him the laws of the Ibur, of sanctifying the new moon. While there, Rav Abuhav’s son said a blessing over a fruit aloud and everyone in the family answered Amen to his blessing. Unintentionally, being over-engrossed in his studies, Rabbi Jaffe did not answer Amen to the blessing. His teacher Rabbi Abuhav became extremely angry at his student and severely admonished him, going to the extent of placing him in excommunication. Rav Jaffe had to leave his teachers home and pleaded to his teacher to accept him back. Several days passed and his teacher’s wrath still did not settle, and he did not agree to forgive his student despite the constant implorations. He asked his teacher why he is deserving of such severe consequences when seemingly he committed an unintentional minor transgression. His teacher replied to him “In truth I love you very much, even more than my children, although you should know that when you did not answer Amen you became liable for death from Heaven, and I needed to nullify this decree through admonishing you and causing you distance and pain. I forgive you now with a full heart. Let me tell you a story that happened in the 1600’s prior to the period of the Chmielnicki massacres. There was a certain pious Jew who heard his son say a blessing over bread and did not answer Amen, and it was decreed upon him to die. This Jew was later informed on to the government and was killed shortly thereafter.”
Is one to specifically recite blessings out loud in order so others can answer Amen?
Some Poskim rule one is to specifically recite blessings aloud in order to have others answer Amen after the blessing. One is to try to have at least two people answer Amen after the blessing. If one suspects that the people who hear his blessing will not answer Amen, then he is certainly to avoid saying the blessing aloud.
The Chabad custom: The widespread Chabad custom is to recite blessings quietly. [This custom however only applies to private blessings, such as over a food or a personal Mitzvah, and only when other people may also desire to eat or perform the Mitzvah, and hence they will be saying their own blessing. If however the blessing will not be said by others, and certainly if the blessing is said on behalf of the public, such as Birchas Hatorah by an Aliyah, then it is to be said aloud. Likewise, in instances that saying the blessings aloud helps educate the listeners in saying the blessing, then it should be said aloud. Likewise, this custom obviously does not exempt one from saying the words properly and with concentration, and only relates to the audibility of the blessing. Those who say the blessing quietly and quickly, swallowing the words, certainly are not doing the proper thing.]
How is one to answer Amen if more than one person is saying a blessing simultaneously?
If two people are saying two different blessings simultaneously, then one is to answer Amen twice, one time on each blessing. It is best to answer Amen V’amen. If however they are saying the same blessing then he is to answer Amen one time. If, however they do not conclude the blessing simultaneously, and there is an interval of Kdei Dibbur between the two conclusions of the blessing, then one is to answer Amen for each conclusion of the blessing. If however, they conclude within Kdei Dibbur of each other, then one can choose when to answer Amen, either with the first person concluding or the second person concluding, and the Amen counts for both of them.
Concentrating on the Amen of the answers:
Some Poskim rule that one who says a blessing is to concentrate on the Amen said by the people who heard the blessing. Other Poskim however rule that it is not necessary to do so. Practically, Admur rules like the former opinion, and so concludes the Rebbe.
B. Children answering Amen:
One is to teach his young children and educate them to answer Amen. From the moment that a child answers Amen he has a portion in the world to come.
C. Towards whose blessing must one answer Amen?
Amen to blessing of if did not hear the entire blessing: One is obligated to answer Amen even if one did not hear the entire blessing from beginning to end, but rater only its end. Furthermore, one is obligated to answer Amen even if he did not hear any words of the blessing from the person saying it, so long as he is aware of the identity of this blessing, [and is not intending to be Yotzei with it], in order so it not be an Amen Yesoma.
Amen to blessing if person changed the dialect of the blessing: If a person changed the dialect of a blessing one is not to answer Amen to his blessing. [Nevertheless, if the person is a G-d fearing Jew and changed the wording of the blessing unintentionally or due to lack of knowledge, some Poskim rule one may answer Amen to his blessing.]
Amen to blessing of Gentiles that are not idolaters: If a gentile recited a blessing amongst one the blessings instituted by the Sages one is to answer Amen if he heard the entire blessing from his mouth. If however, one did not hear the entire blessing from his mouth he may not answer Amen. Kutim have the same status as gentiles in this regard.
Amen to blessing of Idolaters and Heretics: It is forbidden to answer Amen after the blessing of a heretic who is a fervent follower of idolatry. This applies even if one heard the entire blessing from his mouth. [The same applies towards Apikorsim, such as Jews praying in a conservative or reform temple, that one may not answer Amen to their blessings. However, those non-religious Jews that are defined as a Tinok Shenishba, one must answer Amen to their blessing.]
Amen to blessing of children: One is not to answer Amen for a blessing recited by children who are being taught the blessings by their teacher. This is despite the fact that it is permitted to teach the children the proper blessings even not during their appropriate time. If however the children are not saying a blessing in vain, such as they are saying blessings at the appropriate time [such as over food], then one [must] answer Amen to their blessings. [One who does not answer Amen to a blessing is severely punished even if the blessing was said by a child. This applies to both a male and female child.]
Amen to blessings of practicing adults: It is forbidden for adults to recite blessings outside of their appropriate time even if it is done for educational purposes, to teach them the blessings. [Such a blessing is considered a blessing in vain and it is forbidden to answer Amen to such a blessing.]
Is one to answer Amen to the blessing of a Cheresh or Shoteh?
Is one to answer Amen for a blessing of a child who has not yet reached the age of Chinuch?
Some Poskim suggest that one is not to answer Amen for the blessing of a child that has not yet reached the age of Chinuch. Nevertheless, the widespread custom is to answer Amen for the blessing of all children even if they have not yet reached the age of Chinuch.
May one answer Amen to the blessing of a child who is not yet potty trained and has a soiled diaper?
Some Poskim imply it is permitted and an obligation to answer Amen to his blessings, [unless one is the father of the child]. Others however rule it is forbidden to answer Amen. According to all, it is forbidden for the father to educate his child to say blessings while he is soiled with feces [and he should therefore not answer Amen to his blessings in such a case].
May one answer Amen to the blessing of a child who was cleaned but still contains fecal remnant?
Some Poskim rule it is permitted and one is obligated to answer Amen to his blessings if he has not yet reached the age in which he can be held responsible to fully clean himself. This is approximately at age six. Others however rule it is forbidden to answer Amen to the blessing of an unclean child. Practically, the custom of the world is to be lenient.
May one answer Amen to the blessings of one who is praying Shemoneh Esrei aloud?
It is disputed amongst Poskim whether one is to answer Amen to the blessings of a person Davening Shemoneh Esrei aloud. Some Poskim leave this matter in question. Other Poskim rule it is permitted/obligation to answer Amen. Other Poskim rule it is forbidden to answer Amen.
Rosh Hashanah/Yom Kippur: During Rosh Hashanah and Yom Kippur one may answer Amen to a person saying the blessings of Shemoneh Esrei aloud, being that they are not doing a transgression. Nevertheless, it is best to distance oneself from the person in order not to hear his blessings.
 Admur 215:2; Michaber 215:2; Mishneh Brachos 51b
The reason: This is learned from the verse “Ki Shem Hashem Ekra, Havu Godel Lelokeinu”. Moshe said to Bnei Yisrael that when he recites a blessing with Hashem’s name, the listeners are to answer Amen and give praise to Hashem. [M”B 215:8]
 Admur 124:11; 61:4; Levush 124:4
 Admur 124:9; Tur 124
 Admur 124:9
 Admur ibid; Michaber 124:6; Tur 124; Abudarham
 M”A 124:10
 Admur ibid; M”A ibid
 Admur ibid; Taz 124:3; M”A ibid
 Admur 189:6; M”A 215:3 in name of Midrash; Chesed Lealafim 215:4; Kaf Hachaim 215:11
 Admur ibid
Is this a Mitzvah or obligation? From the wording of Admur ibid it is implied that it is not an obligation but a Midas Chassidus and so is also implied from Orchos Chaim Kerias Hatorah 3 who says “It is permitted to answer Amen” and so rules Emek Sheila 53:2. However, some Poskim rule it is an obligation to answer Amen to a prayer or blessing, such as Harachaman. [M”A 215:3 in name of Midrash; Chesed Lealafim 215:4; Kaf Hachaim 215:11]
 See Aruch Hashulchan 215:1; Kaf Hachaim ibid; Piskeiy Teshuvos 215:7 footnote 42
 Toras Menachem 1988 2:245 and 597 [printed in Shulchan Menachem 5:280] that this especially applies to the blessing said to an Avel; Rav SZ”A, brought in Pnei Baruch ibid; Nitei Gavriel 90:2; Piskeiy Teshuvos ibid
 Betzeil Hachochmah 5:90
 Shabbos 119b
 Gemara ibid; Rabbeinu Yona Brachos “Some people’s concentration are aroused through raising their voice.”
 Rashi ibid
 Chayeh Adam 6:1
 See Shach C.M. 382:7; Shaareiy Teshuvah 215:2; Likkutei Sichos 35:216-22
Background: There is an apparent dispute in the Talmud [Brachos 53b; Nazir 66b] as to what is greater; the Amen or the blessing. Each side of the argument seemingly carries a practical ramification in which they would dispute [regarding fine for stolen blessing, and regarding if one should try to lead Zimun]. The Shulchan Aruch in different areas ruled on these ramifications in a seemingly contradictory way. The Poskim [M”A 201:6; Shach C.M. 382:7] who answered this contradiction conclude that Amen is equal to the blessing, but not greater, and therefore the two rulings in Shulchan Aruch stand true, and the final stance is unlike the opinion who says Amen is greater. The Rebbe in Likkutei Sichos 35:216-22 however takes an approach that in truth Amen is greater in one aspect and less great in another and therefore they equal out in reward.
Practical ramification-One who stole a blessing: The practical ramification in whether we say that one who answers Amen is greater than the person who said the blessing is regarding if one stole a blessing from another, such as someone else covered the blood of a bird, must the stealer pay the “owner” ten Zehuvim if the answered, or person could have answered, Amen. Practically, we rule that he is not obligated to pay being that answering Amen is even greater than the blessing. [Rama 382:1; Shach C.M. 382:4 [see there in great length]; Rosh in Chulin end of Perek Kisuiy Hadam in name of Rabbeinu Tam; Mordechai Chulin 655; Tur Y.D. 28; Smeh C.M. 382:7]
Practical ramification-Leading the Zimun: We rule that it is a Mitzvah to lead the Zimun and say the blessing over the Kos Shel Bracha. [Brachos 53b; Nazir 66b-end; Michaber 201:4; Admur 201:5] This implies that we do not rule like the statement in Brachos that answering Amen is greater than saying the blessing. [Simple implication of Gemara ibid that this matter is a dispute, and only according to the opinion who says it is not greater do we hold that one should lead the Zimun; Ravaya Brachos ibid; Piskei Harid Brachos ibid; Kesef Mishneh in opinion of Rambam Brachos 1:11] This contradicts the previous ruling regarding not giving a fine to one who stole a blessing. [M”A 201:6; Madanei Yom Tov on Rosh Chulin 6:8, brought in Shach C.M. 382:7] Some therefore answer that even the opposing opinion agrees that one who answers Amen gets rewarded, and that is why a fine is not given, and not because answering Amen is greater. [M”A ibid; Shach ibid; See Shaareiy Teshuvah 215:2; Panim Meiros 1:57; Birkeiy Yosef 215] Others answer that in truth everyone agrees that there is an aspect of advantage for the Amen over the blessing and an advantage of a quicker reward for the blessing over the Amen and therefore their reward is equal. [Madanei Yom Tov; Likkutei Sichos ibid p. 217]
 Madanei Yom Tov on Rosh Chulin 6:8; Likkutei Sichos 35:216-22 in answer of contradiction brought in coming footnotes
The reason: As he completes the blessing. This is the advantage of Poel over Koach. However, the person who said the blessing is greater in the fact that he started the blessing. [See reasons and coming footnotes and Likkutei Sichos ibid in great length on this subject]
 Brachos 53b; Nazir 66b; Shach C.M. 382:4 in initial explanation [see there in great length and his later explanation]; Tur Y.D. 28; Smeh C.M. 382:7; Levush 215, brought in Shaareiy Teshuvah 215:2; Rosh in Chulin end of Perek Kisuiy Hadam in name of Rabbeinu Tam regarding a stolen blessing; Mordechai Chulin 655; Implication of Semag Aseh 27; Orchos Chaim Dinei Amen; Rashal Hachovel 60; P”M 124 M”Z 4 “So we rule”; See Likkutei Sichos 35:216-22 in great length on this subject!
Other opinions: Some Poskim rule that although the Gemara makes the above statement, nevertheless it is not the final Halachic ruling, and rather we hold like the other opinion in the Gemara ibid that one who answers Amen is equal to one who says the blessing in reward, although Hashem hastens the reward for the person who said the blessing. [M”A 201:6; Shach C.M. 382:4 in later explanation; See Shaareiy Yosef 7 in name of Ritva, brought in Shaareiy Teshuvah 215:2; Panim Meiros 1:57; Birkeiy Yosef 215] See Likkutei Sichos ibid who answers the apparent contradictions and conflicting opinions
 Initial explanation in Shach C.M. 382:4 [see there in great length]; Rosh in Chulin end of Perek Kisuiy Hadam in name of Rabbeinu Tam; Mordechai Chulin 655; Tur Y.D. 28; Smeh C.M. 382:7; Likkutei Sichos ibid
Other opinions: Some Poskim rule that nevertheless a fine is imposed for the stolen Mitzvah. [Rashal Hachovel 60, brought in Shach ibid and negated by him] Some Poskim rule that this Halacha has nothing to do with the above statement of “Amen being greater than the blessing” as even the opposing opinion agrees that one who answers Amen gets rewarded equal, and that is why a fine is not given. [M”A 201:6; Later explanation in Shach C.M. 382:7; See Likkutei Sichos ibid who negates this explanation]
 Likkutei Sichos ibid in answer of contradiction brought in previous footnotes
The reason: As he started the blessing. This is the advantage of Koach over Poel. [ibid]
 M”A 201:6; Shach C.M. 382:7; Brachos 53b; Nazir 66b-end; Likkutei Sichos ibid
 Admur 201:5; Brachos 53b; Nazir 66b-end
 Admur 201:5; Michaber 201:4; Brachos 53b; Nazir 66b-end
 Admur 167:3; Rama 167:2; Darkei Moshe 167:4; Or Zarua based on Yerushalmi; Rosh end of Nazir; Gra 167
 Rebbe Nihoraiy in Brachos 53b and Nazir 66b as explained in Tosafus ibid
 Maharsha Nazir 66b; Likkutei Sichos ibid p. 220; Thus we rule that the person saying the blessing must concentrate on the Amen of the listener. [Admur 167:14; Rama 167:2; Or Zarua 1:102 and 178 based on Yerushalmi Brachos 7:3; P”M 167 A”A 36; Likkutei Sichos 35 p. 220] Furthermore, we find Poskim who rule that if the listener did not say Amen then neither the person who said the blessing or listener fulfill their obligation! [Or Zarua 1:102 and 178, brought in Darkei Moshe 167:4] We do not rule this way. [Darkei Moshe ibid; Likkutei Sichos ibid footnote 44]
 Or Hatorah Bereishis 3:566
 Orchos Chaim Din Aniyas Amen; Abudarham Seder Shacharis Shel Chol; See Zohar p. 229 and 271; Rokeiach 330;
 Rabbeinu Bechayeh Beshalach 14:31
 Perisha 124; See Admur 201:5; Likkutei Sichos ibid p. 218-219 who negates this explanation of Gemara
 Sefer Chassidim 19
 Shavuos 36a; Elya Raba 124:11; Perisha 124; This means that he is accepting the blessing with a swear and faith. See Chasam Sofer 15; See Likkutei Sichos ibid p. 219
 Nehara Hashaleim p. 15, brought in Kaf Hachaim 124:30; Vetzaruch Iyun as explained in Poskim that during learning one is exempt from answering.
 Machatzis Hashekel 6:9 based on Asara Mamaros; Zohar Eikev and Vayeitzei; See Shach C.M. 382:4 in name of Maharshal who writes it is an obligation to recite blessings aloud in order to merit others with Amen and one who does not do so is a Rasha and see Shach ibid that the law that one is obligated to pay 10 Zehuvim for a stolen blessing is only if one could not answer Amen, such as the person who said the blessing said it quietly, and only if one planned to say the blessing aloud; See however Smeh 382:7 and Shach ibid that the above obligation is only by Milah, being it was instituted to be said aloud and in public, however by other Mitzvos, such as Shechita or covering the blood, one may say it quietly and so is the custom; See Bigdei Yesha 167:33 in name of Kisvei Arizal that if one is alone and unable to have someone answer Amen to his blessing he is to say it with great desire and love of Hashem. This concentration creates an angel who then answers Amen to his blessing.
 Zohar ibid; Asara Mamaros ibid; Machatzis Hashekel ibid
 Ben Ish Chaiy Maasey 14
 Heard from Rav Yehuda Leib and Eliyahu Landa Shlita; The Rebbe by Farbrengens was not heard to say blessings aloud, allowing the public to answer Amen; See also Smeh and Shach ibid that only by Milah is it an actual obligation
The reason: As Admur 213:4 rules that one who hears a blessing according to some opinions is Yotzei even if he did not have intent to be Yotzei, and hence, in order to prevent others from entering into this doubt, we therefore recite the blessings silently. [Rav Landa Shlita] According to this reason however, it suffices to simply say the first words quietly [see Admur 215:2] and then say the remainder aloud, hence benefiting from all sides.
 M”B 124:25
 Halachos Ketanos 2:48; Beir Heiytiv 55:1; Kesher Gudal 9:27; Shalmei Tzibur p. 87; Beis Oveid 8; M”B 55:4; Kaf Hachaim 56:8; See Piskeiy Teshuvos 55:6
Other opinions: Some Poskim rule one is to answer after the last person who concluded and it counts also for the first person. [Ashel Avraham Butchach 124:6] See Piskeiy Teshuvos ibid who writes that the Shaareiy Teshuvah 56:3 and Birkeiy Yosef 56:1 argue on the above and rule that one is to only answer Amen to the first person concluding. This is incorrect, as the Birkeiy Yosef and Shaareiy Teshuvah were not discussing the above case but rather a case in which you have many different Minyanim taking place in the same room and you are unable to answer Amen for every Minyan’s Kaddish. The Kesher Gudal [author of Birkeiy Yosef] brings both Halachos, one in 9:27 and one in 9:28, thus proving they do not contradict each other but are rather speaking of two different cases. Likewise, the Kaf Hachaim 56:7-8 records the two rulings in two separate Halachos and referring to two different cases, thus proving it is not a dispute or contradiction.
 Admur 167:14; Rama 167:2; Or Zarua 1:102 and 178 based on Yerushalmi Brachos 7:3; P”M 167 A”A 36; Likkutei Sichos 35 p. 220
The reason: As the Amen is also part of the blessing [Darkei Moshe 167:4; Admur 167:3; Gra 167; Rashi Brachos 47a] and through answering Amen the blessing of the person receives greater importance, and hence it is initially proper to intend to fulfill one’s obligation with the Amen said by the listeners. [Darkei Moshe ibid; Or Zarua ibid; Yerushalmi; M”B 167:20]
 See Biur Halacha 167:2 “Vehamevarech” that so is implied from Lechem Chamudos and Shiyurei Kneses Hagedola, and that aside for the Or Zarua, no other Posek mentioned such a law. This ruling of the Rama [regarding concentration to be Yotzei the Amen] is omitted from Admur in 167:3 and is possibly negated from his wording there, as explained next, however in Admur 167:14 he explicitly rules like Rama ibid. See Likkutei Sichos 35 p. 220 footnote 41
The reason: As there is no obligation for one who says a blessing to say or hear Amen, and on the contrary one who says Amen to his blessing is considered a fool. [Biur Halacha ibid]
 Admur 167:14
Ruling of Admur in 167:3: Admur 167:3 completely omits this ruling of the Rama and Or Zarua regarding concentration. Furthermore, Admur stipulates the entire law of delaying cutting the bread until the Amen has been completed by majority of the congregation to only a case in which the listeners are fulfilling their obligation with this blessing of Hamotzi, and plan to eat bread on its basis. Now, although Admur records the wording of the Darkei Moshe and Or Zarua ibid that Amen is part of the blessing, nevertheless Admur learns that this only applies when the person saying Amen is fulfilling his obligation with the blessing. Perhaps the reason for this is because in truth Admur rules there is no need for the person saying the blessing to concentrate by the Amen, not even in a case that the person saying Amen is fulfilling his obligation. However, nevertheless, he may not cut the bread until the Amen is complete, being that the Amen of one who is being Yotzei a blessing is part of his blessing and the bread is to remain a Shaleim until one completes the blessing. [See Likkutei Sichos 35 p. 220 footnote 41 that leans to learn this way in Beis Yosef and Admur ibid based on their wording, although then brings the real Girsa in Orchos Chaim which implies like Rama and Or Zarua] However, despite the above Diyukim, in 167:14 Admur explicitly rules like Rama and Or Zarua ibid that one must concentrate on the Amen of the listener. Hence, one must conclude that Admur on the one hand holds that one must concentrate to the Amen, and on the other hand holds that one may cut the bread if no one is being Yotzei, as the main thing is that one does not eat the bread prior to the Amen. This would explain why Admur 167:3 changed the wording of the Orchos Chaim and wrote not to cut the bread rather than not to eat the bread. Accordingly, though, Admur argues on the reason of why he cannot break the bread prior to the completion of the Amen and it is not because he needs to be Yotzei it, as he can be Yotzei it even after the breaking prior to the eating, but rather because of the listeners. Vetzaruch Iyun!
 Likkutei Sichos 35 p. 220
 Admur 124:10; Rama 124:7 in name of Kol Bo
 Seemingly this includes even children that are below the age of Chinuch. [See Piskeiy Teshuvos 215 footnote 9]
 Admur 124:11; 215:2; See Biur Halacha 215 “Chayav”; Piskeiy Teshuvos 215:3
 Admur 215:2
Other opinions: Some Poskim rule one is not obligated to answer Amen for a blessing that one did not hear at all and it is merely voluntary to do so. [Kaf Hachaim 124:47; Biur Halacha 215 “Chayav” based on Taz and Mamar Mordechai, brought in Piskeiy Teshuvos 215:3] Based on this some Poskim rule it is best not to answer Amen to such a blessing. [Kaf Hachaim ibid] If however one heard some of the words of the blessing then he must answer Amen. [Kaf Hachaim ibid; Michaber 215:2]
 Admur 215:2; Michaber 215:2
 Kinyan Torah 5:9 based on M”A 53:15
 Admur ibid; Rama 215:2; Rabbeinu Yonah Brachos 51b; Yerushalmi
Other opinions: Some Poskim rule one is never to answer Amen after the blessing of a gentile. [Kesef Mishneh in opinion of Rambam; Bach 215; brought in M”A 215:3; Mateh Yosef, P”M 215 A”A 3 and Kaf Hachaim 215:14 that so is the ruling Michaber who omitted the ruling of the Rama] However, one may answer Amen after a Yishmaeili, being they do not serve idolatry. [Maharikash; Kaf Hachaim 215:15]
 The wording in Admur ibid is “Nachri”, however the Rama ibid writes “idol worshiper”. The M”B 215:12 explains that a common idol worshiper does not intend towards idolatry when saying Hashem’s name and hence one is to answer Amen to his blessing. It is possible to learn this way in Admur as well, as Admur only forbids answering Amen to a person who is fervently attached to idolatry, and hence perhaps your normal gentile would be valid.
If the blessing was not instituted by the Sages: If a Gentile states “may our G-d help you or save you” one should not answer Amen to his blessing. If, however, he says “May your G-d help you or save you” then one may answer Amen. [Sefer Chassidim 427; Chesed Lealafim 215:4; Betzeil Hachochmah 3:39]
Obligation or voluntary: Some Poskim rule one is not obligated to answer Amen for a blessing said by a gentile and it is merely voluntary to do so. [Taz 215:3; P”M 215 M”Z 2; M”B 215:12; Kaf Hachaim 215:14] Admur however omits this opinion and implies that it is obligatory. Vetzaruch Iyun
 Admur ibid; Michaber ibid regarding Apikores; Rambam Brachos 1:13
The reason: (As the common intents of an idolater’s mention of Hashem’s name is towards his idolatry.) [Admur ibid]
 Igros Moshe 2:50
 Piskeiy Teshuvos 215 footnote 29
 Admur ibid; Michaber 215:2-3; Brachos 53b
 Admur ibid; Michaber 215:3; Rambam Brachos 1:15
 M”B 124:47
The reason: A child is obligated to say an obligatory blessing [just like an adult] in order to educate them in Mitzvos. Thus, when they say a blessing at the appropriate time in order to exempt them from their obligation, one is to answer Amen to the blessing. The same applies regarding a child who is reading the Haftorah for the congregation and is saying the before and after blessings, that the congregation is to answer Amen to those blessings. [Admur ibid]
 See Maaseh Shehaya brought above from Nehara Hashaleim p. 15, brought in Kaf Hachaim 124:30
 Piskeiy Teshuvos 215 footnote 45; However see Aruch Hashulchan 215:2 that it does not apply towards a female child. See Yabia Omer 2:13
 Admur ibid; M”A 215:8; Elya Raba 215:4; See Igros Kodesh 3:138
The reason: Although the blessings recited by the children for the purposes of learning are blessings in vain, nevertheless the Sages permitted it to be done. However, by an adult, it is forbidden for him to say blessings outside of their appropriate time even if he is doing so for the sake of learning. [Admur ibid]
 P”M 124 A”A 14; M”B 124:47
 M”B 215:16 that so is implied from the Peri Megadim on Miseches Brachos; M”B 124:47
What is the age of Chinuch? Some say the age of Chinuch is five years old. [Yabia Omer 8:25] Others write it is from the time the child knows how to say the blessing on his own. [Salmas Chaim 134; See Piskeiy Teshuvos 215:8 footnote 44]
 Even Yisrael 8:14; See Piskeiy Teshuvos ibid footnote 46; Or Letziyon 2:14
 See Divrei Chaim 2:9; Misgeres Hashulchan on Lechem Hapanim in Kitzur SHU”A 165:1; Tiferes Adam 3:6; Piskeiy Teshuvos 215 footnote 49
 See Misgeres Hashulchan ibid
The reason: As a child who is not old enough to be educated to clean himself, only the father is obligated to clean him. Thus, if a person [other than the father] hears his blessing, he must answer Amen towards it. [Misgeres Hashulchan ibid]
 Kitzur SHU”A ibid in Lechem Hapanim
The reason: As it is forbidden for an adult to say a blessing while he has fecal remnant in his anus opening, and the same would apply to a child who is being educated in Mitzvos. [ibid]
 Divrei Chaim 2:9; Misgeres Hashulchan on Lechem Hapanim in Kitzur SHU”A 165:1; Tiferes Adam 3:6; Piskeiy Teshuvos 215 footnote 49
The reason: As if the child is not old enough to be educated to clean himself then he is exempt from this aspect of Chinuch. Even the father is exempt from cleaning him to such a point that no fecal remnant remains by his opening, as the child is not old enough to do so himself. Thus, it ends up that although the child is obligated in being educated for blessings he is exempt from this level of cleanliness. [Misgeres Hashulchan ibid in lengthy explanation and defense of ruling of Divrei Chaim ibid]
 Misgeres Hashulchan ibid
 Kitzur SHU”A ibid in Lechem Hapanim
The reason: As it is forbidden for an adult to say a blessing while he has rectal fecal remnant and the same would apply for a child. [ibid]
 Misgeres Hashulchan ibid, as if we were stringent we would need to wait until age six to begin teaching the child Torah and blessings, and this certainly is not done, as we begin educating children from a very young age.
 Chochmas Shlomo 124; Mishmeres Shalom 11:1
 Yabia Omer 8:10 [Obligated answer Amen]; See Yagel Yaakov 42
The reason: As he has not swerved from the dialect of the Sages.
 Alef Hamagen 582:43; Shevet Halevi 3:15; Halichos Shlomo 8:32 in name of Rav SZ”A
The reason: As he is praying against the rulings of the Sages. [ibid] Vetzaruch Iyun regarding one who Davens aloud in private, in which case he may do so for concentration. [See Piskeiy Teshuvos ibid; Halichos Shlomo ibid]
 Alef Hamagen ibid; Shraga Hameir 5:105
Obligation or voluntary: Some Poskim rule one is obligated to answer Amen for such a blessing. [Betzeil Hachacham 5:164] From other Poskim however it is implied it is not obligatory. [See Halichos Shlomo ibid; Piskeiy teshuvos 215 footnote 35