As contemporary religious Jewry is comprised of many culturally diverse groups, it is not uncommon for one to pray in a synagogue that follows different practices than those to which he is accustomed. Such scenarios raise the question of when an individual’s liturgical practices are allowed to differ from those of his fellow congregants. May someone who ordinarily prays in nusach Ashkenaz do so even in a congregation that follows nusach Sefarad? May one respond to kedusha in the fashion in which he is accustomed?

The Talmud (Yevamos 13b) derives the prohibition of agudos agudos from the passuk in D’varim, “Lo sisgodidu” (14:1). While the literal reading of the verse prohibits self-mutilation as a sign of mourning, the Talmud provides an additional interpretation, suggesting that the verb form lo sisgodidu indicates “lo sa’asu agudos agudos,” or “do not make yourselves into divergent groups.” This prohibition applies specifically to courts that condone divergent halachic practices within a unified constituency.

Minhagim
Two reasons for the prohibition of lo sisgodidu emerge from Rishonim, and there may be practical differences between the reasons. According to Rashi (Yevamos 13b s.v. lo sa’asu) if Jewish courts condone two divergent practices in a single region, it will appear as if there are two “Torah”s, two legal systems. Rambam (Avodah Zarah 12:14, Pe’er HaDor 151) views the prohibition as simply intending to limit machlokes (disputes).

Presumably Rashi and Rambam will disagree about lo sisgodidu’s application to minhag, common practice not rooted in objective halachic requirements. Regarding Rashi’s reasoning, the condoned practice of divergent minhagim does not convey the impression that the judicial system recognizes two “Torah”s. However, according to Rambam - who maintains that the purpose of the prohibition is to limit disputes - disputes about minhagim arise with no less frequency than disputes about strictly halachic practices.

Rambam in fact is explicit, both in Yad Hachazakah, ibid, and in his responsa (262), in codifying lo sisgodidu in regard to minhagim. The particular query addressed to Rambam involved a community whose longstanding practice was to sit for kedushas yotzeir of the brachos preceding krias shema. A new rabbi who lacked the stature and wisdom of his predecessors arrived in town and began standing for this part of the services, and a handful of congregants followed his lead. Rambam responded that the new rabbi’s practice was an incorrect minhag, and having a situation in which some congregants stood while others sat constituted a violation of lo sisgodidu. In practice we accept the ruling of Rambam, as Rama (Orach Chayim 493) discusses lo sisgodidu in the realm of minhag, specifically in the context of mourning practices during the period of sefiras ha’omer, the days between Pesach and Shavuos during which 24,000 of Rabbi Akiva’s students died.

Beis Din
The Talmud indicates that practical applications of lo sisgodidu may be significantly limited. According to Abaye, if two courts functioning in two different cities provide divergent rulings, they do not violate lo sisgodidu. The prohibition only applies to two courts in the same city that rule differently, as when one follows Beis Hillel’s position and the other follows Beis Shamai’s position. Rava disputes Abaye’s view and claims that lo sisgodidu applies exclusively to a single court within which half of the members rule one way and the other half rule another way. Rava assumes that two courts, even if they function within the same jurisdiction, are entitled to different opinions, just as two sages may disagree about halachic rulings. Abaye presumably distinguishes between two sages, who are allowed to hold their own opinions and two functioning courts in the same city, which must reflect a uniform opinion when defining popular practice.

Some Rishonim limit even Abaye’s more expansive definition of this prohibition. The first Mishna in Megilla provides for villagers to read the megilla on an earlier date than city dwellers. According to many Rishonim, the villagers would congregate in the cities to read the megilla on an earlier date. [Rabbeinu Chayim (quoted in Tosafos Yevamos 14a s.v. ki amrina) holds that the villagers would read on the earlier date in their own villages. This is also the opinion of the Rav Av Beis Din (R’ Avrohom ben Yitzchok of Narvonne) as quoted in Ramban and Rashba s.v. amar Abaye.] This practice appears to be equivalent to two courts in the same city providing divergent rulings, which Abaye prohibits. The Rashba explains that since the villagers were recognizable as a separate entity in the cities, they were considered residents of another city and thus not subject to lo sisgodidu. Further indicating the distinct identity of visiting villagers, the Rashba in Megilla (2a s.v. ela) indicates that they had their own established lodgings in the cities and everyone knew that people from a given village would congregate at a specified point in the city.

As a general rule, the halacha follows Rava’s opinion when he disputes Abaye (see Bava Metzia 22b). Yet Rambam apparently supports Abaye on the issue of lo sisgodidu, prohibiting two courts in the same city from issuing divergent rulings (Avoda Zara 12:14). Kesef Mishna quotes two explanations for Rambam’s ruling, suggesting either that Rambam did not mean what he wrote literally or that there is a scribal error in our texts of Rambam. Kesef Mishna also suggests that the rule that we follow Rava over Abaye does not apply when their disagreement reflects a dispute that existed in generations prior to Abaye and Rava.

Netziv (Meishiv Davar 17:4) writes that Rambam in fact follows Rava but understands Rava’s opinion differently. Rava’s prohibition of a split court applies exclusively to a situation in which the entire court agrees in principle to a lenient position but half of the court wants to follow in practice a more stringent position. Rava would agree that even when two courts function in one city, a given court that agrees in principle with a lenient position practiced by the other court cannot apply the more stringent position. When Rambam prohibits two courts in the same city from issuing divergent rulings he refers specifically to this case.

Since Jewish communities today generally lack a single unchallenged judiciary body, practical applications of lo sisgodidu arise mostly in synagogue settings. Accommodation of divergent practices within the same synagogue approximates a single court with half its judges ruling one way and half the other way. Next week we will discuss instances of lo sisgodidu that can arise in contemporary situations, specifically as relates to changes in nusach hatefillah and wearing or not wearing tefillin on Chol Hamoed.