The Talmud relates two prohibitions connected to the avoidance of disharmony: “Lo titgod’du (Devarim 14:1)” and the prohibition to deviate from the custom of the place one is in (minhag ha-makom) in the interest of avoiding “machloket” (Pesachim 51-52). While these comprise two distinct prohibitions (see, at length, Resp, Sridei Eish, II, Y.D. 11 in 5759 ed.), they share many overlapping themes. The Talmud (Yevamot 14a). perceives a dual meaning in the phrase, lo titgod’du,( “you shall not cut yourselves [in anguish over a lost relative]”) referring not only to physical cutting but condemning as well the creation of agudot agudot, separate and distinct groups within the community. (Whether the word “groups” is used precisely, or whether perhaps even one person with divergent practices presents a problem, is the subject of a question posed to R. Yosef Chaim Sonnenfeld in Responsa Salmat Chaim 883. See also Turei Even, Megilah 2a, in Avnei Shoham (and note objection of R. Yehonatan Elishberg, printed in the journal Moriah, nos. 239/220:305); Resp. Tzofnat Paneach (Dvinsk 5700), Even HaEzer 61; and R. Shimon Gabel, Kli Golah to Yevamot. The possibility that the prohibition is directed only at those who instruct others in halachic practice is considered in R. Yisrael Yosef Bronstein, Avnei Gazit, p. 332-3.) Whether this is to be taken as an actual interpretation of the text, or rather a rabbinically assigned allusion (asmachta), is a matter of some dispute. (On the former position, see Kessef Mishneh, Hilkhot Avodat Kokhavim 12:14; Responsa Me’il Tzedakah 49; Eishel Avraham (Pri Megadim) 493:6; Responsa Meishiv Davar 3:37:5; and Sdei Chemed, Klalim, Ma’arekhet Halamed, Klal 78; and Gur Aryeh to Devarim; on the latter, Sefer HaMitzvot L’HaRambam, prohibition 45; Mayim Chaim to Mishneh Torah; Sha’ar Yosef to Horayot 7b; R. Eliyahu Mizrachi to Devarim; and Torah Temimah to Devarim. On both, see Mitzvot HaShalom, pp. 129-131; She’erit Yosef 4:42; Avnei Gazit (p. 324-6). R. Moshe Feinstein, Responsa Iggerot Moshe, Orach Chaim, vol. 4, no. 34, assumes the prohibition is biblical.) R. Tzvi Zesherovsky, Minchat Tzvi 467, observes that there is a thematic connection between the two prohibitions derived from this verse, self-mutilation in mourning and communal fracture. The linkage is suggested by the beginning of the verse, “You are children to the Lord your God.” The Jewish people realize that as children of God, all that occurs is ultimately for the best, thus, there is no reason to grieve in a drastic, inappropriate manner. So, too, the Father of the Jewish people would be anguished by unnecessary division among His children. The latter version of the prohibition is stated in relevance to halakhic practice: “Abaye said… such as two rabbinical courts within one city, one ruling like Beit Shammai and one like Beit Hillel;… Rava said, like one rabbinical court in a city, half of the court ruling like Beit Shammai and half like Beit Hillei.” The rishonim present varying perspectives on the essence of this prohibition. Rashi, (Yevamot 14a, s.v. El Hatam) and many others, identify the problem as giving the appearance that the Jewish people are governed by two Torahs, that each group possesses its own body of halakhah not shared by the other. This is problematic for several reasons, one of which is that it presents an idolatrous image. Also, as R. Shmuel Landau (In his father’s Resp. Noda B’Yehudah, II, Y.D. 29) observes, blatant divisions among Jews create a desecration of God’s Name. The Rambam (Hilkhot Avodat Kokhavim 12:14), however, seems to understand the motivation to be avoiding the conflicts that inevitably arise when separate groups are formed, at odds with each other. This is also the position of the Sefer HaChinnukh (Mitzvah 467). The Netziv (Resp. Meishiv Davar 1:17) observes that Rashi’s understanding appears more consistent with the discussion in the Talmud, where this objection is raised in relation to the various dates established for the reading of Megillat Esther in different cities. Grounded in an inherent difference in the status of the cities, this variation is unlikely to evoke controversy; however, a case could be made that it does give the appearance of two Torahs. The Ritva (13b, s.v. Vi’Akati.) comments on the talmudic derivation in a manner amenable to both reasons. The interpretation is suggested by the beginning of the verse: “You are children to the Lord your God.” All of Israel is children to one God, as opposed to that which may be indicated by multiple Torahs, or by a divided nation. As the Netziv observes further, if the central concern is the appearance of two Torahs, then following the logic mentioned earlier, divergences in matter of custom should not pose a problem, as it is accepted as a matter of course that different people have different customs (Note also the Netziv’s comments in his Ha’amek Davar to Chumash.). However, if the fear is the risk of conflict, it is an unfortunate reality that issues of custom are not immune from this danger. (See Responsa Maharshdam, Yoreh Deah 356; R. Shlomo Wahrman, She’erit Yosef 4:42; and the journal HaPardes, vol. 7 no. 64:25-27; Avodat Melekh, to Hilkhot Avodat Kokhavim; Birkat Avraham, Pesachim, p. 329; Responsa Beit Av 93; Adnei Paz 29; R. Yechezkel Sarna, in Kovetz Nehorai L’Zekher Nishmat R. Meir Kotler, p. 91-102; R. Yaakov Aharon Rothman, Sefer Zikkaron Beit Abba, p. 255; Be’er Avraham pp. 104-106; R. Aharon Soloveichik, Parach Mateh Aharon, Mada, pp. 172-173; Avnei Gazit (p. 329-32); and R. Yosef Roth, Siach Yosef 22. For a wide-ranging discussion of this and all aspects of the prohibition, see R. Yaakov Zev Smith in the journal HaMetivta 5749:235-273.) Accordingly, the Rambam and the Sefer HaChinnukh, mentioned previously as proponents of the latter rationale, do apply the prohibition to issues of custom, as does the Smag (Prohibition 62). The Magen Avraham (O.C. 493) also appears to agree with this position. The Netziv (Meromei Sadeh, Yevamot 14a) observes that despite the obligation to adhere to personal custom, derived from “Do not abandon the Torah of your mother,” this prohibition overwhelms that imperative. This question bears great relevance to issues of communal prayer. (Concerning prayer, see Resp. HaRadbaz 3:474 and 534; Resp. Avkat Rokhel 32; R. Resp. U’Bacharta BaChaim 24 and Resp. HaElef Likha Shlomo 45; Resp. Meishiv Davar; Resp. Rivv’vot Ephraim 2:44; Resp. Avnei Yoshpe 117; Yashiv Moshe, p. 10 (rulings of R. Yosef Shalom Eliashiv); Resp. V’Darashta V’Chakarta (vol. 1, Orach Chaim, 21); and R. Moshe Tzuriel, in the journal Sha’alei Da’at 7:101-106. In regards to wearing tefillin on Chol HaMoed, about which there are differing halakhic opinions, see Shulchan Arukh, O.C. 33:2 and Rama, Eishel Avraham (Buchatch) ibid.; Resp. HaBach HaChadashot 42, Resp. Maharsham 3:359; Resp. HaAlshikh 59; Resp. Sha’arei Deah, Tinyana 7; Resp. Heishiv Moshe 31; Resp. Teshurat Shai 486; Resp. Beit Yitzchak, Yoreh Deah 2:88; Resp. Zikhron Yehudah 115; Resp. Beit Lechem Yehudah 110; Responsa Divrei Yissakhar 4; Sefer Ot Chaim V’Shalom 31; Resp. Menuchat Moshe 90; Artzot HaChaim 31; Magen Giborim 31; Resp. Chatan Sofer 427; Resp. Levushei Mordechai, Tinyana, O.C. 423; Resp. Hillel Omer, O.C. 320; Resp. D’var Shmuel 322; Resp. Da’at Sofer, vol. 3, O.C. 2; Resp. Shemesh Tzedakah 90:15; Resp. Ginzei Yosef 32:2, Ohr Avraham 4; and Resp. Iggerot Moshe, O.C., vol. 4, no. 34 (see also no. 305:5, as well as his words in the memorial volume Mevakshei Torah for R. Shlomo Zalman Auerbach, vol. 2, pp. 461-5). Many of these forbid a situation in which, in one synagogue, some wear tefiliin on Chol Hamoed and some do not; although some are lenient. R. Moshe Shternbuch (Responsa Teshuvot V’Hanhagot 2:31, and note also 2:80) tends toward leniency based on his suggestion that the responsibility of lo titgod’du is to bring the matter before a bet din for final decision; as no modern court is empowered to decisively rule on a question such as this, no prohibition pertains. For an interesting perspective on some of the basic positions see R. Ya’akov Davidson, Hilkhot Derekh Eretz, ch. 24. Note R. Chaim Leib of Krakow, Chayyei Aryeh 9, cited in Sdei Chemed, Ma’arekhet Chol Hamoed, #16, who does not apply the prohibition to issues of disputed halakhic ruling. R. Yechiel Yaakov Weinberg, in a lengthy responsum (Resp. Sridei Eish, ibid.) that includes a critique of the Netziv’s position, concludes that while lo titgod’du is indeed limited to matters of actual law, there exists, as noted above, an additional prohibition, specifically addressed to customs, that prohibits differentiated behavior in situations of potential strife, thus mandating adherence to minhag hamakom. This prohibition is a formidable one that R. Weinberg gives much attention to. Returning to lo titgod’du, some poskim have suggested that a distinction exists between long-standing, established customs and those more recent and less entrenched. Some authorities considered the variant customs of Ashkenazim and Sefardim to be so well-known and acknowledged as to be untouched by this prohibition. Those lenient on this point include R. Mordechai Benet, Parashat Mordechai, Orach Chaim 4, and Em HaRo’im, Ma’arekhet Lamed; see R. Moshe Halberstam, Responsa Divrei Moshe 35, and Resp. Be’er Chaim Mordechai, #4. (However, see also Responsa Chatam Sofer 6:1; Pe’at HaShulchan, Hilkhot Eretz Yisrael 3:32; R. Moshe Mintz, Responsa Maharam Mintz 15; and R. Moshe Shick, Responsa Maharam Shick, Orach Chaim 43. See, as, well, R. Yitzchak Hershkowitz , Responsa Divrei Ohr 9.) Along these lines, many rishonim suggest that a mitigating factor present in the multiple options for Megillah reading is the fact that no side believes the other is acting in an incorrect or prohibited manner, rather according to a prearranged and understood differentiation. It would appear that the primary concern is thus the fear of discord; if each side recognizes the other’s right to act in a different manner, this consideration is nullified. This guideline is adopted by R. Yosef Chaim Sonnenfeld in his responsa (Salmat Chaim 874-882.), as well as by others. Accordingly, R. Yehudah Leib Litwin (Sha’arei Deah 2:7, cited in R. Yitzchak Sternhill, Kokhvei Yitzchak 3:7:2) and the Arukh HaShulchan (Orach Chaim 551:22) rule that for issues that are not halakhically indispensable, this prohibition is not a concern. Similarly affected by this evaluation is a situation in which the entire population agrees to allow two modes of practice. The consensus would apparently obviate concerns of strife, but the appearance of two Torahs would still be a danger. The latter position is considered normative by some (see Shulchan Arukh HaRav, Orach Chaim 493:7, and Resp. Zikhron Betzalel 22), while others disagree. Further, if the issue is disharmony, it may become less problematic if one or both of the parties is unaware of the divergency. So, too, if the variation is not obvious; thus, leniency is more easily conceivable for actions done in silence. (See Resp. Meishiv Davar; Resp. Shoel U’Meishiv, Mahadurah Talitai 1:247; Yam Shel Shlomo, Yevamot 3:10; Resp. Avnei Nezer, O. C. 29; and Resp. Iggerot Moshe, O.C. 2:94.) The Resp. Me’il Tzedakah (50), however, forbids multiple practices in the same area even when not simultaneous to each other, apparently, his concern is more with the appearance of two Torahs. A similar position is held by Turei Even to Megilah 19a (in Avnei Shoham). Of course, as R. Moshe Halberstam (Resp. Divrei Moshe 35) observes, it is very possible that both proposed rationales for the prohibition are accepted as halakhah. If this is indeed the case, then the stringencies of both would be operative; effort must be taken to avoid any differentiation that risks either causing a conflict or giving the appearance of two Torahs (R. Halberstam uses this reasoning to reconcile a difficulty in the rulings of the Rama, O.C. 493:3). R. Halberstam’s son-in-law, R. Mattisyahu Deutsch, independently adopts a similar perspective in his response (Resp. Netivot Adam, 5), but suggests a distinction that affects the above mentioned discussion in reference to customs. Granted, adopting a dual stringency approach would forbid divergence in customs, as the risk of conflict is present, even if the “two Torahs” concern is not. However, in the case of long established customs that have become identified with a particular group, the entrenched nature of these customs will eliminate any basis for dispute. Thus, such divergence should be permitted, even within an enclosed area, as neither risk is present. To support his point, R. Deutsch cites Responsa Emek haTeshuvah (#112), who posits that the prohibition of lo titgod’du is only binding on individuals who are empowered to act differently; in other words, are not bound by any preexisting and established practice. Such a distinction would thus exempt the situation discussed by R. Deutsch. (It should be noted,t hough, that this suggestion appears incompatible with the Netziv’s words cited earlier.) In any case, it appears that at least the Rambam, if not others, finds this prohibition to be the source for the Torah’s opposition to conflict. R. Avraham Sherman (In the journal Ohr HaMizrach, nos. 130/131:272-280.) suggests that the Rambam prefers this as a source to the aforementioned possibilities because, as interpreted by the Talmud, it indicates that the prohibition is applicable even when the quarreling centers on matters of halakhah. R. Moshe Weinberger (In the journal HaMetivta 5756:181-185) proposes that inherent in this prohibition is an obligation to attempt, through dialogue, a consensus that will eliminate the need for any divisions.