The Talmud states that one who has only enough for either Chanukah candles or “household candles” [according to most, the Shabbat candles (See Ritva to Shabbat 23b, and R. Yosef Engel, Gilyonei HaShas citing Responsa Halakhot K’tanot 2:181)], the candle of his house takes precedence, for the sake of a peaceful household (mishum sh’lom beito). The Rambam (Hilkhot Megillah V’Chanukah 4:14) expands on this, adding, “for the Name is erased in order to make peace between a man and his wife; great is peace, for the entire Torah is given to make peace in the world, as it says, ‘Its ways are ways of pleasantness, and all of its paths are peace.’ ” Thus, the Rambam elaborates significantly, joining the concept to that of the erasing of God’s name. R. Avraham Friedlander (in Har HaMelekh to Hilkhot Chanukah) suggests that this is to indicate not merely preference to shalom but absolute prioritization. For example, not only should limited funds be spent on candles rather than on wine for kiddush, as candles represent shalom, but even if one has already purchased wine for kiddush but cannot afford candles, the wine must be sold in favor of the candles. The Lubavitcher Rebbe (in the journal HaMa’or, vol. 50, no. 6:311) explains that the Rambam is not claiming that the Shabbat candles are more important than Chanukah candles or than Kiddush; in fact, their rabbinical origin would place them on equal or lesser footing than the latter mitzvot. Rather, the result of the fulfillment of this mitzvah, shalom, is more all-encompassing than the others. This is evidenced by the Rambam’s concluding his words by noting that “the entire Torah is given to make peace...” As this is the case, showing precedence to the cause of peace is consistent with the goals of all mitzvot, and thus the course of action that will reap the most spiritual benefit.
This sensitivity has continued into the later generations. The Pardes Yosef, Vayikra 26:3, relates that R. Chaim of Volozhin recommended dispensing with a controversy concerning a slaughterer suspected of not properly inspecting an animal’s lung, observing that inspection of the lung is a rabbinical requirement, while strife is a biblical prohibition. R. Yisrael Pesach Friedlander (Responsa Avnei Yoshpe, Yoreh Deah 126) weighs this aspect heavily in considering whether a brit may be held later in the day, in spite of the requirement that it be held as early as possible. Preserving harmony factors heavily in several responsa of R. Ezra Basri: to allow a flagrant sinner to remain in place as cantor of a congregation (Responsa Sha’arei Ezra I, 5); to assign to a mitzvah performed in a contentious manner the invalid status of mitzvah haba’ah ba’aveirah, a commandment fulfilled through a transgression (I, 19); and to be factored among those elements that may justify the charging of minor forms of interest (avak ribbit) (I,52). The Torah Temimah, Bamidbar 16:16, suggests that even according to the rejected position in the Talmud that a Torah scholar is not permitted to waive his honor, he may do so for the purposes of peace.
The Talmud (Berakhot 30b) states that one should not enter into prayer while under the influence of any of a number of improperly conducive emotions, among these anger and contentiousness. In light of this and of the previous passage, the Radbaz (Responsa, III, :472) points out that in choosing a synagogue, and a seat within the synagogue, the ability to get along with the surrounding congregants must be taken seriously into account. He even goes as far as to consider, although prefacing with an apprehensive lulei d’mistafina, “were that I were not afraid,” that praying at home without a minyan is preferable to joining one that will lead to an experience of disharmony. R. Yehoshua Tzvi Michel Shapiro (Kuntres Imrot Tihorot, ch. 12) endorses the overall concept, while disagreeing with the last detail; he infers that this is also the position of R. Yonatan Eibshutz (Comments printed in Sefer Halakhah Achronah and Kuntres Hara’ayot in Sefer HaPardes, p. 8b) and assumes that the Radbaz, too, would agree for practical purposes.