דברים פרק יד
(א) בָּנִים אַתֶּם לַיקֹוָק אֱלֹהֵיכֶם לֹא תִתְגֹּדְדוּ וְלֹא תָשִׂימוּ קָרְחָה בֵּין עֵינֵיכֶם לָמֵת:
You are children of the Lord, your God. You shall neither cut yourselves nor make any baldness between your eyes for the dead.
אמר ליה ר"ל לר' יוחנן איקרי כאן (דברים יד) לא תתגודדו לא תעשו אגודות אגודות. א"ל עד כאן לא שנית מקום שנהגו לעשות מלאכה בערבי פסחים עד חצות עושין מקום שנהגו שלא לעשות אין עושין
Reish Lakish said to R’Yochanan: Read the verse “Lo Titgodedu”, which means do not form separate groups... He replied to Reish Lakish: We learned in a Mishna “In a place where people have the custom to do work on the day before Pesach until midday, one may do work. But in a place where they have the custom not to do work, then they may not”
פרקי אבות ב:ה
הלל אומר, אל תפרוש מן הציבור, ואל תאמין בעצמך עד יום מותך, ואל תדון את חברך עד שתגיע למקומו, ואל תאמר דבר שאי אפשר לשמוע וסופו להישמע. ואל תאמר לכשאפנה אשנה, שמא לא תפנה.
Perkei Avot 2:5
Hillel Taught: Do not withdraw yourself from the community; Do not be sure of yourself until the day you die; Do not judge other people until you stand in his situation; Do not say “It is not possible to understand this” for eventually it will be understood; Do not say “When I have free time I will study”, for you may never have free time.
רמב"ם הלכות עבודת כוכבים פרק יב הלכה יד
ובכלל אזהרה זה שלא יהיו שני בתי דינין בעיר אחת זה נוהג כמנהג זה וזה נוהג כמנהג אחר, שדבר זה גורם למחלוקות גדולות שנאמר לא תתגודדו לא תעשו אגודות אגודות.
Rambam Hilchot Avodat Kochavim 12:14
This commandment also includes [a prohibition] against there being two courts which follow different customs in a single city, since this can cause great strife. [Because of the similarity in the Hebrew roots,] the prohibition against gashing ourselves [can be interpreted] to mean: "Do not separate into various different groupings."
רמב:ם הלכות תשובה פרק ג הלכה יא
הפורש מדרכי צבור ואף על פי שלא עבר עבירות אלא נבדל מעדת ישראל ואינו עושה מצות בכללן ולא נכנס בצרתן ולא מתענה בתעניתן אלא הולך בדרכו כאחד מגויי הארץ וכאילו אינו מהן אין לו חלק לעולם הבא העושה עבירות ביד רמה כיהויקים בין שעשה קלות בין שעשה חמורות אין לו חלק לעולם הבא
RambamHilchot HaTeshuva 3:11
One who separates himself from the Community, even if he does not commit a transgression, but only holds aloof from the congregation of Israel, does not fulfill religious precepts in common with his people, shows himself indifferent when they are in distress, does not observe their fast, but goes his own way, as if he were one of the gentiles and did not belong to the Jewish people -- such a person has no portion in the world to come.
Rabbi Avraham Yitzchak Kook, Orot, p. 144
The relationship between the Jewish people and its individual members is different than the relationship between any other national group and its constituents. All other national groups only bestow upon their individual members the external aspect of their essence. But the essence itself each person draws from the all-inclusive soul, from the soul of God, without the intermediation of the group... This is not the case regarding Israel. The soul of the individuals is drawn from ... the community, the community bestowing a soul upon the individual's. One who considers severing himself from the people must sever his soul from the source of its vitality. Therefore each individual Jew is greatly in need of the community. He will always offer his life so that he should not be torn from the people, because his soul and self-perfection require that of him.
Rabbi Joseph B. Soloveitchik, On Repentance, pp. 114-115
Judaism has always viewed man from this dual perspective. It sees every person as an independent individual and also as part of a community, a limb of the body of Israel. Jewish thinkers have conducted an ongoing dialectic on this subject throughout the ages. The pivotal question is: Does the individual stand above the community which should serve its needs, or should the individual subordinate himself to the community's needs? In Judaism this question has been asked in relation to the individual who serves as a community leader. Who, in our history, was a greater leader than Moses, redeemer of Israel, the great rabbi and teacher, about whom our Sages wrote that his worth was equivalent to that of six hundred thousand men, meaning the total number of the male community of his time? Nonetheless, when the children of Israel fashioned the Golden Calf, "God said to Moses, 'Go down - lower yourself down; for did I not grant you greatness only to benefit Israel? And now that Israel has sinned, what need have I of you?'" (Berakhot 32b). Even the greatness of an individual like Moses is dependent upon the community. It would seem that the community and the individual are placed in balance with each other and are interdependent. At times we find that the community must sacrifice itself on behalf of the individual ... And at times the individual must sacrifice himself for the good of the community.
Never is the individual's worth belittled when measured against the whole community; and never is the community undermined because of any individual or individuals. Each has its own position of strength.
שולחן ערוך אורח חיים הלכות פסח סימן תסח: ד
ההולך ממקום שעושין למקום שאין עושין,לא יעשה בישוב מפני המחלוקת; אבל עושה הוא במדבר. וההולך ממקום שאין עושים למקום שעושין, לא יעשה...ואעפ"כ לא יתראה בפניהם שהוא בטל, מפני איסור לעולם אל ישנה אדם מפני המחלוקת
Shulchan Aruch Orach Chaim 468:4
Rabbi Joseph ben Ephraim Caro was born in Toledo, Spain in 1488, and died in Safed in 1575
One who goes from a place that does something to a place that doesn’t do it, he should not do the action because it might cause arguments, but he can do it in private. If one goes from a place that does not do an action to a place that does, he does not need to do that thing...nonetheless he should not show to others that he is doing differently because of causing arguments.
שו"ת בצל החכמה חלק ה סימן א ד"ה ו) עוד
...בספר אמרי בינה להגאון מקאליש ודעתו שגם אם כל הצבור יושב בשעת קריאת התורה מותר ליחיד להחמיר על עצמו ולעמוד, דכיון דמבואר בטו"ז דלדעת מהר"ם מדינא צריך לעמוד ... על כן רשאי כל אחד לחוש להחמיר על עצמו, ע"ש. - ולענ"ד להמבואר לעיל (אות ד' - ה') ה"ה להיפך, שגם אם כל הצבור עומד רשאי כל יחיד לישב ...ממילא דלא שייך בזה הא דאמרו (סופ"ז דמס' דרך ארץ רבה) שלא יהיה עומד בין היושבים ולא יושב בין העומדים, דזה דוקא באין טעם לדבר אבל בדאיכא טעם נכון מותר...
Shu”t Batzel Chochma 5:1
R. Betzalel Stern, was born in Hungary in 1911, and died in Jerusalem in 1989, after serving time as a rabbi in Australia.
In the book Amrei Bina he says that even if the entire congregation sits during Torah reading, an individual is allowed to stand, because both the Taz and Maharam say that one must stand...In my opinion, that the law also applies to the opposite, that even if the entire congregation is standing, one is allowed to sit.. this does not contradict the Mishna (Derech Eretz Rabbah), “there shouldn’t be a person standing amongst those sitting, and there shouldn’t be a person sitting amongst those standing” for that is only in a place where there isn’t a reason to do the opposite...
Shu”t Siach Nachum- Shaving on Chol Hamoed, Sfirat Haomer, and Bein Hameitzarim
This is all said when there is a clear prohibition, such as they prohibited shaving during chol hamoed, and so there is no reason to say anything. But the prohibitions during the Omer, are rarely spoken about by the Rishonim, and the Rambam doesn’t mention it at all, but the Tur (Orach Chaim 493) writes: “And there are places that don’t get haircuts.” And even in later generations not all communities took on this minhag...
And we find, that even in places that had the minhag of not getting a haircut, it seems that it was only talking about the hair on one’s head. And even today, there are many people who are shomrei mitzvot who do not keep this minhag, and we can’t really have this conversation, unless it is a place that everyone follows this minhag...
Every minhag like this, each person needs to think about their family and their community, so they are not considered “sitting amongst the standing or standing amongst the sitting” (Derech Eretz Rabba 7), because this will cause anger and arguments. Because this is a very sensitive subject, I tell all who ask to do as his father did, so not to dishonor his father. And even if his father gives him permission to act differently, anyone who sees a father walk with his son, and one is clean shaven and one has facial hair, it could reflect badly on the father or the son...