Responsa for Pesachim 100:12

All the customs for which the Sages said that one should follow the custom, that is for a custom made to prevent a transgression such as the one in Pesachim 50: a place in which it is customary to do work on the eve of Passover until noon one does work, and if not to do work one does not. For according to the Torah it is forbidden to do work from noon onwards, for it is the beginning of the time to slaughter the Passover sacrifice. And there are places where they distanced and refrained from work the entire day, and the custom should not be changed. And likewise, the Mishnah (Pesachim 53): in places with a custom to sell small animals to non-Jews one sells, places with a custom not to sell one does not; in places with a custom to eat roasted meat on Passover eve one eats, in places with a custom not to eat one does not; in places with a custom to light candles Yom Kippur eve one lights, in places with a custom not to light one does not; in places with a custom (Pesachim 54) to work on the 9th of Av one works, in places with a custom not to work one does not. And it says in Pesachim 50 As the mishna discusses the requirement to observe local customs, the Gemara relates: The residents of Beit She’an were accustomed not to travel from Tyre to market day in Sidon on Shabbat eve. Their children came before Rabbi Yoḥanan. They said to him: Due to their wealth, it was possible for our fathers however, it is not possible for us to do so. He said to them: Your fathers already accepted this virtuous custom upon themselves, and it remains in effect for you, as it is stated: “My son, hear your father’s rebuke and do not abandon your mother’s teaching” (Proverbs 1:8). All these customs are to distance from Torah transgressions. And the Sages said not to change them. But if there is a custom in a place to transgress, it should be changed even if great rabbis follow the custom, for a court cannot remove a biblical law, even the Sanhedrin in Jerusalem has no such right, except to withhold action but not to perform actions. Even a prophet is not heeded, unless he is established as Elijah on the Carmel, who was obeyed to offer sacrifices outside the temple on a special occasion. And not only should one change a custom to transgress, but also a custom to distance from transgression bit which may result in transgressions should be changed. As it is said in Perek Makom Shenahagu (Pesachim 50b): The residents of the city of Ḥozai were accustomed to separate hallah from rice dough. They came and told Rav Yosef about this custom. He said to them: Let a non-priest eat this dough in their presence to show them unequivocally that this custom has no legal basis. For we are concerned that they will end up mixing up what is permitted with what is forbidden. For from this custom they will think that rice is a type of grain. This is also in the Yerushalmi: If you become unsure of the Halakha do the customary, meaning that if there is a loosening in the Halakha, you become unsure of what the Halakha is, and you see the customary actions of others, then follow their customs. For you can rely for the great rabbis to lead others to follow the Halakha. But if you are sure of knowing the Halakha you have no right to follow the custom that contradicts the Halakha. This is the ruling for customs related to what is permitted and forbidden. In financial matters the courts have the power to make financial regulations according to the times and needs. Even to transgress a Torah law and to transfer assets from one to another, per the Baraita in the first Perek of Baba Batra 8a: Similarly, it is permitted for the residents of the city to set the measures, the prices and the wages, and to fine people for violating their specifications. And it is said in Yevamot Perek Ha'Isha Raba (89): As Rabbi Yitzhak said: From where is it derived that property declared ownerless by the court is ownerless? As it is stated: “And whoever does not come within three days, according to the council of the princes and the Elders, all his property should be forfeited...” (Ezra 10:8). Rabbi Elazar says that the proof is from here: “These are the inheritances that Elazar the priest, and Joshua, son of Nun, and the heads of the fathers’ houses of the tribes...” (Joshua 19:51). What do heads have to do with fathers? This comes to tell you: Just as fathers bequeath to their sons anything they want to, so too, the heads bequeath to the people anything they want to. And all this by making regulations that declare one person's assets ownerless and give it to another. But according to a custom I do not know how they take money from one to another. Understandably with transgressions the custom spreads so that everyone in one place considers the same act a transgression. Even if in other places it is permitted, such as a certain fat that is eaten in Israel but not in Babel. Also working on Passover eve and Av 9th and others. But in finance when the early Sages introduced a marital custom for which there is no source nor hint to allow the wife to bequeath her assets to whom she wishes. And later generations continued this custom to allow the wife to bequeath to whom she wishes. And the scribes wrote and the witnesses signed, even though this is certainly a mistake. And even if there was a judge in the generation who permitted what was written, and through this, the custom is spread and perpetuated. This is not a custom on which one may rely to take assets from one to another. For one may only transfer assets by a court order. Certainly if the judge based his ruling on the early Sages we would listen. But I have seen that judges rule to begin with that the wife has the right to bequeath to whom she wishes, without relying on the earlier ruling, but believe this is the halakha. And it is not permitted to transfer assets, it can only be declared ownerless by the court. Also heard of a judge who ruled in agreement to an earlier judge, but was not able to justify his ruling; he just considered it the custom since he followed the earlier judge. And I said this is not appropriate. Even if judges repeated the same judgment generation after generation based on the first ruling, it is a mistaken custom, and it has to be abolished. For it allows a Torah transgression to move assets away from the rightful heir, other than allowing the court to declare assets ownerless. Also when Sages setup a regulation they obligated others to follow it, without additions nor detractions. And if later Sages wish to add to or detract from the regulation they need to first abolish the first regulation and then to institute a new one as they wish. And as long as they did not do so, there is no power in a custom to abolish a regulation. Asher ben HaRav Yechiel.