Reish Lakish said to him: Do you hold that Beit Shammai actually acted in accordance with their own statement? Beit Shammai did not in fact act in accordance with their own statement, as the dispute was merely theoretical. And Rabbi Yoḥanan said: Beit Shammai certainly did act in accordance with their opinion. The Gemara comments: And this is also reflected in the dispute between Rav and Shmuel, as Rav says: Beit Shammai did not act in accordance with their own statement, and Shmuel said: They certainly did act in that manner.

The Gemara inquires: When does this question apply? If we say that it is referring to the period prior to the Divine Voice that declared that the halakha is in accordance with the opinion of Beit Hillel, then what is the rationale of the one who said that Beit Shammai did not act in accordance with their opinion? But rather, if one would say it is referring to after the Divine Voice, what is the reason for the one who said that they did act in accordance with their opinion? After all, the Divine Voice established that the halakha is in accordance with the opinion of Beit Hillel.

The Gemara answers: Neither of these options poses a difficulty. If you wish, say that it is referring to the period prior to the Divine Voice, and if you wish, say instead that it is after the Divine Voice. The Gemara elaborates: If you wish, say it is prior to the Divine Voice, and it is referring to the period when Beit Hillel formed the majority of the Sages. Therefore, according to the one who said that Beit Shammai did not act in accordance with their opinion, the reason is that Beit Hillel was the majority, and the halakha is in accordance with the majority.

And the one who said that they did act in accordance with their opinion maintains that when do we follow the majority? It is in a case where the disputing parties are equal in wisdom to one another. Here, however, Beit Shammai are sharper than Beit Hillel, and therefore they acted in accordance with their own opinion despite the fact that they were in the minority.

And if you wish, say instead that it was after the Divine Voice. The one who said that Beit Shammai did not act in accordance with their opinion would say that this was due to the pronouncement of the Divine Voice. And the one who said that they did do so, this is in accordance with the opinion of Rabbi Yehoshua, who said, with regard to the Divine Voice that emerged and proclaimed that the halakha is in accordance with the opinion of Rabbi Eliezer in the case of the oven of akhnai (Bava Metzia 59b), that one disregards a Heavenly Voice. Just as he disregarded the Divine Voice in his dispute with Rabbi Eliezer, so too, one disregards the Divine Voice that proclaimed that the halakha is in accordance with the opinion of Beit Hillel.

And yet the question remains: According to the one who said that Beit Shammai acted in accordance with their opinion, we should read here: ''You shall not cut yourselves'' (Deuteronomy 14:1), which is interpreted to mean: Do not become numerous factions. Abaye said: When we say that the prohibition: ''You shall not cut yourselves'' applies, we are referring to a case where two courts are located in one city, and these rule in accordance with the statement of Beit Shammai and those rule in accordance with the statement of Beit Hillel. However, with regard to two courts located in two different cities, we have no problem with it.

Rava said to him: But the dispute between Beit Shammai and Beit Hillel is considered like a case of two courts in one city, as these two schools of thought were found everywhere, not in any specific place. Rather, Rava said: When we say that the prohibition: ''You shall not cut yourselves'' applies, we are referring to a case where there is a court in one city, a section of which rules in accordance with the statement of Beit Shammai and another section rules in accordance with the statement of Beit Hillel. However, with regard to two courts located in one city, we have no problem with it.

§ The Gemara cites other relevant sources. Come and hear: In the locale of Rabbi Eliezer, where his ruling was followed, they would cut down trees on Shabbat to prepare charcoal from them to fashion iron tools with which to circumcise a child on Shabbat. In Rabbi Eliezer’s opinion, not only does the mitzva of circumcision override Shabbat, but also any action required for the preparation of the tools necessary for the circumcision likewise overrides Shabbat. The baraita adds: In the locale of Rabbi Yosei HaGelili they would eat poultry meat in milk, as Rabbi Yosei HaGelili held that the prohibition of meat in milk does not include poultry.

The Gemara infers: In the locale of Rabbi Eliezer, yes, they would act in this manner, whereas in the locale of Rabbi Akiva, for instance, no, they would not do so, as it is taught in a baraita that a principle was stated by Rabbi Akiva: Any prohibited labor that can be performed on Shabbat eve does not override Shabbat even if it involves a mitzva. A mitzva whose proper time is on Shabbat overrides Shabbat only if its performance was impossible earlier, e.g., the act of circumcision itself, which cannot be performed earlier.

The Gemara asks: And what is this refutation? As stated above, it is different when dealing with numerous places, and the baraita explicitly states that this practice was followed in Rabbi Eliezer’s locale. Consequently, there is no violation of the prohibition against splitting into factions. The Gemara asks: He who asked it, why did he ask it, i.e., what is the basis for the question in the first place? It is obvious that the baraita is referring to a specific place.

The Gemara answers: It might enter your mind to say that due to the severity of Shabbat, it, i.e., the world, is considered like a single locale. In other words, one might have thought that the permission to tolerate diverse customs in different places applies only to other prohibitions, whereas the prohibition of Shabbat is so severe that it is unacceptable to allow different customs, as this might lead people to disrespect Shabbat. Therefore, the baraita teaches us that even in the case of Shabbat there can be different customs in various locales.

§ The Gemara cites another relevant case involving Shabbat: Come and hear that Rabbi Abbahu, when he happened to come to the place of Rabbi Yehoshua ben Levi, would move an oil lamp [sheraga] after the flame that had been lit for that Shabbat had burned out, as Rabbi Yehoshua accepted the ruling that it is permitted to carry items of this sort that had been set aside. But when he happened to come to the place of Rabbi Yoḥanan, who prohibited carrying items of this kind that had been set aside on Shabbat, he would not move an oil lamp. This indicates that divergent customs are followed in different places.

Again, the Gemara asks: And what is this difficulty? Didn’t we say that it is different when dealing with numerous places? The Gemara explains that this is what we are saying: With regard to Rabbi Abbahu himself, how could he act in this manner here and how could he act in that manner there?

The Gemara answers: Rabbi Abbahu holds in accordance with the opinion of Rabbi Yehoshua ben Levi that it is permitted to carry this item. And when he happened to come to the place of Rabbi Yoḥanan he would not carry it, in deference to Rabbi Yoḥanan, so as not to act contrary to his ruling in the place where he was the authority. The Gemara asks: But there was a servant accompanying Rabbi Abbahu who would see him carrying these types of articles that had been set aside. Wasn’t Rabbi Abbahu concerned that the servant might carry them in Rabbi Yoḥanan’s locale? The Gemara explains that he would inform the servant and explain to him the reason for his change in behavior.

§ The Gemara continues to discuss the question of whether Beit Shammai followed their own rulings. Come and hear that which is taught in the mishna: Although Beit Hillel prohibit and Beit Shammai permit, and these disqualify the women and those deem them fit, Beit Shammai did not refrain from marrying women from Beit Hillel, nor did Beit Hillel refrain from marrying women from Beit Shammai. Granted, if you say that Beit Shammai did not act in accordance with their opinion, it is due to that reason that they did not have to refrain from marrying women from Beit Hillel. However, if you say that they did act in accordance with their opinion, why didn’t they refrain from marrying one another?

The Gemara elaborates: Granted, Beit Shammai did not refrain from marrying into Beit Hillel, as even if Beit Shammai maintain in a certain case that a rival wife required levirate marriage or ḥalitza, if she went ahead and married another man their children are born to a union whose partners are liable by a regular prohibition: ''The wife of the dead man shall not be married outside'' (Deuteronomy 25:5). Since this transgression does not entail karet, the children of this relationship are not mamzerim.

However, why did Beit Hillel not refrain from marrying into Beit Shammai? In the opinion of Beit Hillel the children of these rival wives who entered into levirate marriage are born of a union whose partners are liable to receive karet, as the prohibition of a brother’s wife was never nullified in this case, which means that the children are mamzerim. If so, how could Beit Hillel allow these marriages?

And if you would say that Beit Hillel maintain that the child of a union whose partners are liable to receive karet is not a mamzer, as a mamzer is only one whose parents violated a prohibition that entails the death penalty, didn’t Rabbi Elazar say: Although Beit Shammai and Beit Hillel disagreed with regard to rival wives, they concede that a mamzer is only from a union whose prohibition is a prohibition of forbidden relations punishable by karet? Consequently, the children of rival wives are mamzerim according to Beit Hillel. Rather, isn’t it correct to conclude from here that Beit Shammai did not act in accordance with their own opinion?

The Gemara rejects this conclusion: No; actually, Beit Shammai did act in accordance with their opinion. As for the problem with these marriages, the answer is that they would inform Beit Hillel and Beit Hillel would withdraw from the match. When those who acted in accordance with the opinion of Beit Hillel would come to marry women from those who followed the rulings of Beit Shammai, they would be notified that certain children were born of rival wives and that those people were considered mamzerim in the opinion of Beit Hillel, who therefore declared them forbidden in marriage.

The Gemara comments: And so too, it is reasonable that this is the case, as the mishna teaches in the latter clause: With regard to all of the disputes concerning the halakhot of ritual purity and impurity, where those, Beit Hillel, rule an article ritually pure and these, Beit Shammai, rule it ritually impure, they did not refrain from handling ritually pure objects each with the other.