Davening with a Minyan
A person should make a great effort to daven in a minyan because of the tremendous holiness of davening in a minyan and because when one prays in a minyan one's Tefillot are accepted before Hashem.  Some hold that there is a rabbinic obligation to go to a minyan and joining is a Biblical mitzvah in the enhancement of one's Tefillah, while others hold it is a very important religious value that one should not forgo but not an absolute obligation.
Being Enthusiastic to Go to Minyan
- It is praiseworthy for one to run to shul, demonstrating one's eagerness to do mitzvot.
Where to Go to Minyan
- If one has the choice of going to a closer shul or a farther shul, one may choose the latter option, as one gets more reward for one's journey (Sechar Pesiot, but one must understand that it comes at the opportunity cost of Talmud Torah and could possibly entail Shmiras Eynayim issues.
Coming to Minyan Early
What Parts of Davening Require there to Be a Minyan?
- A congregation may not say Kaddish, Kedusha, or Barchu with less than a minyan, meaning a quorum of ten adult men.
- According to the halacha, it is permissible to start Chazarat HaShatz even if 4 people in the minyan are still davening the silent Shmoneh Esrei. However, it is better to wait until there are ten who are able to answer before starting Chazarat HaShatz.
What is Considered Davening with a Minyan?
- Is davening Shemona Esrei when the tzibur is davening a different Shemona Esrei is that considered tefillah btzibur? Many achronim that it is considered tefillah btzibur, while many others disagree.
- Someone from Diaspora who is davening a weekday Shemona Esrei with an Israeli minyan on the second day of Yom Tov that is considered Tefillah Btzibur. In the opposite case with an Israeli in the Diaspora davening a weekday Shemona Esrei with the congregation davening a Yom Tov Shemona Esrei is a dispute if that is Tefillah Btzibur.
Davening in an Adjacent Room
- If there is a larger room and a smaller room completely open to that larger one if the majority of the minyan is in the large room that is considered one minyan. If the majority of the minyan is in the small room they don't combine.
- Some say that as long members of the minyan can see each other they can join together for a minyan. One should only rely on this opinion in an extenuating circumstance.
Who Counts for a Minyan?
- A minimum of ten Jewish free adult men are necessary to form a minyan.
- A child can't be counted for a minyan. There is an opinion who allows counting a child for the tenth person if there's nine other adults. Ashkenazim can rely on that upon in an extenuating circumstance. Many poskim say not to rely on that opinion even in an extenuating circumstance.
- Though a deaf-mute is generally assumed to have the status of a Shoteh, there is much debate as to whether or not he is considered a Bar Da'at and can count for a minyan if he attended a special education school and learned how to communicate. As such, if there are only ten people, one may count him for a minyan but should only do a short Chazara, so as not to risk too many Berachot Levatala.
- Someone who isn't religious can be counted for a minyan.
If Some of the Minyan Left Early
- If there are only 10 men in the minyan, none of them may leave in middle. However, if there are more than 10 men, those who are in excess of 10 may leave if they already heard Barchu, Kedusha, and all the Kaddishim.  If one already heard the Barchu, Kedusha, and Kaddishim and by leaving there won't be a minyan he may not leave in the middle of Kaddish, Kedusha, or any activity that requires a minyan but he may do so between activities. For example, if he was part of the minyan for Kedusha he may not leave until after the Kaddish Shalem after Shemona Esrei since that is one unit. However, if he was part of a minyan for Barchu he may leave before Chazarat Hashatz.
- After the fact, if there are less than ten men left, they one's left are allowed to finish what they had started as long as there are at least 6 men left. 
- If the Shaliach Tzibbur began Chazarat HaShatz he may finish Chazara including Kedusha, but there is no Nesiyat Kapayim and he may not say Kaddish after the Chazara. 
- If the minyan began Kriyat HaTorah and then part of the minyan left (four or less), the one's remaining may finish the Kriyah but may not do Hosafot and the Maftir is said without brachot. 
Missing a Minyan for Business Purposes
Missing a Minyan for Vacation
- A person should not travel from a place where there is a minyan to a place where there is no minyan unless there is a serious health need, parnasa (financial support for oneself and family) need, or mitzvah need.  However one should not go on a tiyul (trip) if it means missing praying with a minyan. 
Missing Minyan in order to Host Guests
Missing Minyan in order to Daven Vatikin
Missing Minyan Because One Is Sick
- One is only exempt in cases of extenuating circumstances such as someone not feeling well and even in such a case one should at least pray at the time of the Tzibbur. 
Missing Minyan Because of Learning
- Someone who’s learning is his “occupation”, meaning that one does not waste any time not learning except for the absolutely necessary activities, may daven without being part of a minyan from time to time, however, nowadays using this leniency is highly discouraged.  Therefore, even if one is involved in learning one should make sure to daven with a minyan and there is an added seriousness for such a person to daven with a minyan so that others do not judge him incorrectly or mistakenly learn out of his actions that davening in a minyan is unimportant. 
- If one came late to the set minyan and going to a later one will cause you to miss learning in a chevruta, one should still daven with the later minyan. 
- If it is going to cause a loss of teaching Torah in public such as if one will miss giving a public shuir, one should miss minyan in order not to miss that opportunity of giving shiur. 
Missing Minyan to daven at a More Optimal Time
- If one always davens vatikin one can daven then by oneself rather than daven with a minyan later. Sephardim would prefer davening with a minyan later unless one has more kavana at vatikin.
- If the only minyan available is one that davens after Olot before Meshyakir many say that it is better to daven by oneself. Some disagree. See When_Is_the_Earliest_and_Latest_Time_to_Pray?#Pre-Msheyakir
- If the only minyan available is one that davens after Olot before Netz, some say that it is better to daven by oneself and some hold that it is better to daven with the minyan. See When_Is_the_Earliest_and_Latest_Time_to_Pray?#Pre-Netz
- If the only minyan available is davening after the third hour of the day it is better to daven with the minyan and say Shema earlier rather than daven by oneself. Some have a doubt about this case.
- If the minyan is davening during Ben Hashemashot after Shekiya, according to Ashkenazim it is better to daven oneself before Shekiya, and according to Sephardim it is preferable to wait for the minyan rather than daven by oneself before shekiya. See When_Is_the_Earliest_and_Latest_Time_to_Pray?#Ideal_Time_for_Mincha
- According to Sephardim it is ideal to daven mincha ketana and not mincha gedola. Yet, if the only minyan available is one that prays at mincha gedola it is preferable to daven with them rather than daven on one's own.
- If the only minyan available is one that is before tzet hakochavim after shekiya one should daven with them rather than daven by oneself. There's a minority opinion that advises praying oneself.
- If the only minyan available is one that is before shekiyah after plag mincha when one already said mincha before plag mincha one should daven with the minyan rather than daven by oneself.
- If the only minyan available is one that is before shekiyah after plag mincha when one already said mincha after plag mincha one should daven by oneself rather than join such a minyan.
On an Airplane
- Many poskim rule that one should not make a minyan when flying on an airplane. 
- Shulchan Aruch 90:9 writes that a person should make a serious effort to daven with a minyan and one is only exempt to do so in extenuating circumstances. Mishna Brurah 90:28 emphasizes the importance of davening with a minyan and that the most important part of davening with a minayn is Shmoneh Esrei. Kitzur Shulchan Aruch 12:7 writes that Hashem does not reject the Tefillah of a congregation even if there are wicked people in the congregation. See Halichot Shlomo (chapter 5 note 52 pg 66) who records an incident in which for health reasons a certain person was only able to leave the house once a day and Rav Shlomo Zalman said he can use that one time to go to work instead of going to daven in a minyan because being social will make him feel better.
- Igrot Moshe OC 4:68 explains that it is forbidden to daven a Tefillah in a place where one knows that one won't be answered. Since davening with a minyan is a certain way to increase the ability of one's Tefillah to be answered (Brachot 8a) it is considered a Biblical enhancement of Tefillah to daven with a minyan. However, the actual obligation to go out of one's way to go daven in a minyan is only rabbinic (Pesachim 46a). Rav Yitzchak Yosef (Motzei Shabbat Shemini 5778 around min 15) explained that going to a minyan is an obligation and Shulchan Aruch's language is only meant to exempt someone sick.
- The Netsiv in Meromei Sadeh 6b s.v. kol writes that someone who always goes to a minyan it is considered a good practice that after doing it consistently it is an obligation upon to keep it like a vow. Rav Hershel Schachter (Brachot Shiur 9 beginning) explained that the Netsiv holds that there's no rabbinic obligation to daven in a minyan, however, being that one's Tefillah stands a better change of being answered in a minyan (Brachot 8a) it is very important value to daven in a minyan.
- BI"H, Perashat Miketz, 2
- Yechave Daat 2:9, note the Torah Lishmah quotes that one only gets extra Sechar Pesiot for walking, not driving.
- Shulchan Aruch 90:14
- Shulchan Aruch 55:1
- Shulchan Aruch 69:1 Mishna Brurah 69:8, Yalkut Yosef (90:14, Sherit Yosef 2 pg 341)
- Halacha Brurah 55:18-9, Mishna Brurah 55:32
- Magen Avraham 90:16 and 236:3 writes that it isn't. His proof is from Avoda Zara 4b that forbad davening Mussaf on Rosh Hashana at home within the first three hours of the day when the Tzibur is davening Shacharit in Shul. However, the Eliya Rabba 236:7 argues that it is considered tefillah btzibur if you are actually in the shul. Tzlach Brachot 6a writes that even the Magen Avraham would agree with the Eliya Rabba if he was actually in the shul together. Magen Giborim A"H 90:14, Pri Megadim M"Z 236:4, and Mishna Brurah 90:30 agree. [However, Halacha Brurah 90:26 proves that this Tzlach is incorrect because of the Magen Avraham 236:3.]
- Rav Yitzchak Elchanan in Bear Yitzchak 20 proves from the Yerushalmi Brachot 4:6 that the Magen Avraham is correct that it isn’t considered tefillah btzibur even if you’re in the same shul davening together with them a different Shemona Esrei unlike the Tzlach. Igrot Moshe OC 4:68 argues with his proof but agrees with the Magen Avraham. Halacha Brurah 90:26 cites the dispute. Shalmat Chaim 113 agrees with the Tzlach but see the footnote which understands that he never meant that.
- See Dirshu 90:32 who cites the Chavaselet Hasharon 2 and Orchot Rabbenu v. 1 p. 51 that even the Tzlach never meant that it is considered tefillah btzibur.
- Yom Tov Sheni Khilchato (9:6 cited by Dirshu 90:32) quoting Rav Shlomo Zalman Auerbach and Rav Elyashiv
- Yom Tov Sheni Khilchato (ch. 3 fnt. 43-5, cited by Dirshu 90:32)
- Gemara Eruvin 92b. Tosfot 92b s.v. Tisha explains that the gemara is relevant to joining together for a minyan. Shulchan Aruch O.C. 55:16 quotes this gemara as the halacha.
- Shulchan Aruch O.C. 55:14
- Mishna Brurah 55:57
- Shulchan Aruch, Orach Chayim 55:4
- Can women count for a minyan? The Mor Ukesiah 55 s.v. katuv bmordechai quotes the Mordechai in the name of the Rabbenu Simcha that women can join a minyan of ten. (The actual text of the Mordechai Brachot n. 158 only quotes Rabbenu Simcha regarding zimun of ten and not a minyan.) The Mor Ukesiah concludes that obviously the halacha is like the other rishonim who hold that a woman can not count for a minyan. That is the opinion of the Tosfot Brachot 45b s.v. vha, Tosfot Rabbenu Yehuda 45b s.v. vha, Tosfot Harosh 45b s.v. vha, Rambam . That is the opinion of Shulchan Aruch 55:4. Why?
- Gilyonei Hashas Brachot 45b (quoted by Daf Al Hadaf) explains the reason that women can't join for a dvar shebekedusha is because they don't automatically inherit land of Israel and anyone who doesn't have a part of the land of Israel isn't considered connected to the Kahal Yisrael (Horiyot 6b). He explains that converts can join as a rabbinic enactment.
- Mor Ukesiah 55 s.v. katuv bmordechai explains that women can't count for a minyan because of kavod hatzibur.
- Can women be counted for a minyan for megillah? Meiri Brachot 47b s.v. amar hameiri nashim writes that women count for a minyan for megillah since they are equally obligated in that mitzvah. However, the Tosfot Rabbenu Yehuda 45b s.v. vha and Tosfot Harosh write that women don’t even count for a minyan for megillah.
- Rabbi Yehoshua Ben Levi (Brachot 47b) said that a child can be counted for a minyan. The Rif doesn't count this statement. The Ramban (Milchamot 35b) explains that the Rif held it wasn't accepted since the gemara on 48a says we don't follow any of the earlier statements on the topic of minyan and zimmun. Ravyah (cited by Mordechai Brachot 172), Rambam Tefillah 8:4, and Rashba Brachot 48a s.v. veleyt agree. However, Tosfot 48a s.v. veleyt quotes Rabbenu Tam who held that Rabbi Yehoshua Ben Levi was never rejected. The Ri disagreed and adds that Rabbenu Tam himself never followed his opinion in practice. Rosh Brachot 7:20 and Mordechai Brachot 172 quote the dispute of Rabbenu Tam and Ri and add that Rav Hai Goan agreed with Rabbenu Tam. Baal Hameor Brachot 35b agrees with Rabbenu Tam. (Raavad on Rif implies he disagrees with the Raavad.)
- Orchot Chaim (Tefillah 73) records a story in which the Rabbenu Shimshon put a town in excommunication for disobeying his ruling and counted a child for a minyan. On the the opposite extreme the Kolbo ch. 11 at the end writes that the minhag of all of Yisrael is to count a child for a minyan. Bet Yosef 55:4 writes that this is an exaggeration.
- Tosfot s.v. veleyt writes that even according to Rabbenu Tam you can only count one child and not multiple children. However, the Baal Hameor suggests that you can even count up to four children as long as there's six adults. Mordechai Brachot 172. Magen Avraham 55:5 writes that even in extenuating circumstances we only follow Rabbenu Tam and not the Baal Hameor. Mishna Brurah 55:24 agrees.
- Tosfot writes that there's no advantage of having the child hold a sefer torah because a sefer torah isn't a person and doesn't add anything for a minyan. The Rama 55:4 writes that those who counted a child for a minyan didn't have them hold a sefer torah. Magen Avraham 55:4 writes that in his day the minhag was to count a child specifically holding a sefer torah.
- Shulchan Aruch 55:4 rules that one can't count a child for a minyan at all. Rama argues that there's what to rely upon in extenuating circumstances.
- Mishna Brurah 55:24 writes that the Levush writes that the minhag is that we never rely on counting a child and also many poskim hold that one shouldn't count a child even in extenuating circumstances.
- Yechave Daat 2:6
- Igrot Moshe OC 1:23 writes that since we learn the idea of a minyan from the meraglim it is acceptable to include someone who violates Shabbat for a minyan in order to say kaddish and kedusha, however it wouldn't be considered tefillah btzibur.
- The Yerushalmi Megillah 4:4 writes that it is forbidden for someone to leave a minyan and upon him the pasuk says that one who abandons Hashem will be destroyed (Yishayahu 1:28). This is quoted by the Rif Megillah 13b, Rosh Megillah 4:7, Rambam Tefillah 8:6, and Bet Yosef 55:2. Darkei Moshe 55:1 cites Mordechai Megillah 810 who says that if there's still a minyan left it is permitted to left the minyan. Rama 55:2 codifies this. Kitzur Shuchan Aruch 15:10 and Mishna Brurah 55:14 clarify that it is only permitted to leave if there's still a minyan left and one already heard every Barchu, Kedusha, and Kaddish until Aleinu.
- Mishna Brurah 55:12
- Kitzur Shulchan Aruch 15:10
- Kitzur Shulchan Aruch 15:10
- Kitzur Shuclhan Aruch 15:10
- Mishna Brurah 90:29
- Halichot Shlomo (5:4 pg 61) writes that for parnasa, health, or mitzvah needs one may travel to a place where one will not be able to find a minyan.
- Theoretical discussion: [Rav Zalman Nechemyah Goldberg (Halichot Shlomo (page 72 and 358) at first writes that seemingly it would be permissible to put oneself in a situation where one will be without a minyan as long as the time for that tefillah did not arrive, similar to the Baal HaMoer who permits boarding a boat 3 days before Shabbat even if one might need to violate Shabbat for Pikuach Nefesh. (The reason for 3 days is that there is an extension of Shabbat into the last three days of the week, however, the obligation of tefillah only applies at the time of prayer). However, he strongly rejects this by saying that putting oneself in a situation of missing praying with a minyan because it would be out of one's control to get a minyan in one's destination is totally dissimilar to violating Shabbat for Pikuach Nefesh which is permitted. He says that going to such a place is like not building a Sukkah for Sukkot and trying to claim that it is out of one's control to sit in the Sukkah. He continues that perhaps the exemption from traveling more than a mil to find a minyan is not because of it being out of one's control, but that the obligation of minyan was removed by chazal for someone at such a distance, similar to someone beyond a certain distance at the time of korban pesach, then perhaps there would not be a prohibition to put oneself in such a situation. He leaves the question whether there is an obligation to find oneself in a place where there is a minyan (before the time of tefillah) unanswered, nonetheless, it is certain that the correct righteous practice would be not to put oneself in such a situation.] Rabbi Aryeh Lebowitz explained that this question would be dependent on another dispute whether davening in a minyan is an absolute obligation or an added feature to davening.
- Rav Nevinsal in BeYitzchak Yikra 90:18
- Halichot Shlomo (chapter 5 note 25 pg 66)
- Halichot Shlomo 5:17
- Shulchan Aruch 90:9, Mishna Brurah 90:29
- Rama 90:18, Mishna Brurah 90:56, Piskei Teshuvot 90:23 writes that this leniency is discouraged but there is what to rely on and quotes the son of the Chafetz Chaim who writes about his father when writing the Mishna Brurah would go ten hours at a time learning without eating or even stopping for mincha.
- Shulchan Aruch 90:18, Mishna Brurah 90:29, 57, See Sh”t Igrot Moshe 2:27 regarding missing minyan for learning
- Mishna Brurah 90:56 writes that one who is going to give a shuir to the public may not miss out on the opportunity in order to go to a minyan. Halichot Shlomo 5:16 adds that even if one will only miss learning with a chevruta one should not go to the minyan; BeYitzchak Yikra (Rav Nevinsal) 90:18 writes that if a student in a yeshiva eats and sleeps by the yeshiva it is an imperative to daven in the yeshiva minyan and it is forbidden to daven in an even holier place such as by the Kotel because of Mitzvah HaBah BeAvierah!
- Mishna Brurah 90:56 writes that one who is going to give a shuir to the public may not miss out on the opportunity in order to go to a minyan.
- Biur Halacha 58:1 s.v. umitzvah
- Yalkut Yosef 89:18
- Biur Halacha 89:1 s.v. yatza, Avnei Yishfe p. 167 quotes Rav Elyashiv, Pri Yitzchak s.v. nachzor 1:2
- Avnei Yishfe p. 168 quoting Rav Ben Tzion Abba Shaul, Igrot Moshe 4:6 s.v. im ken
- Sh”t Sheilot Shmuel OC 12, Rav Elyashiv (quoted in Avnei Yashfei Tefillah page 167), Yalkut Yosef (Tefilla pages 137-139, 89:14)
- Rabbi Yisrael Belsky (OU Kosher Webcast, min 19:30-28:30), Igrot Moshe 4:6 s.v. im ken, Peri Yitzchak 1:2, Sh"t Yaskil Avdi 5:10, Sh"t Minchat Yitzchak 9:10, Chazon Ish (Ishei Yisrael 13:note 21)
- Rama 46:9, Igrot Moshe O.C. 4:6 s.v. im ken
- Biur Halacha 46:9 s.v. ki) isn't sure whether the Gra would prefer to daven by oneself with Kriyat Shema in the right time with Brachot and then juxtapose Shema to Shemona Esrei or not.
- Mishna Brurah 233:14
- Yalkut Yosef 89:16, Chacham Ben Zion Abba Shaul (cited in Ishei Yisroel page 296) and Chacham Ovadia Yosef (Yechave Daat 5:22)
- Yalkut Yosef 89:15
- Shulchan Aruch 235:1
- Even though the Gra (Maaseh rav n. 65 cited by Biur Halacha 235:1 s.v. vim) davened by himself rather than daven with the minyan before tzet, Igrot Moshe 2:60 s.v. val kol panim writes that since it is against most rishonim one shouldn't follow it unless one follows the Gra for everything. Piksei Teshuvot 235 fnt. 26 quotes the Kesot Hashulchan 26:12 who writes that if someone always davens before tzet hakochavim he should continue to do so without a minyan rather than daven early with a minyan.
- Shulchan Aruch O.C. 235:1, Mishna Brurah 235:8
- Shaar Hatziyun 235:16 writes that one shouldn't daven with a minyan before shekiya if on that same day one already davened mincha after plag hamincha.
- Halichot Shlomo page 95, Igrot Moshe OC 4:20, Rabbi Hershel Schachter on torahweb.org