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: it was possible for our fathers; however, it is not possible for us. He said to them: Your fathers already accepted this 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.”

The residents of the city of Ḥozai were accustomed to separate ḥalla from rice dough. They came and told Rav Yosef. He said to them: Let a non-priest eat this dough in their presence! Abaye raised an objection to him: "With regard to matters that are permitted, but others were accustomed to treat them as a prohibition, you are not allowed to permit these actions in their presence."

Rav Yosef said to Abaye: And wasn’t it stated about this halakha concerning stringencies that Rav Ḥisda said: This was stated specifically with regard to Samaritans?

What is the reason that this applies to Samaritans? They will extend this matter of leniency. These people of Ḥozai will also extend this matter of leniency!

Gufa - Back to the previous issue. If matters are permitted but others were accustomed to treat them as a prohibition, you are not allowed to permit these actions in their presence. Rav Ḥisda said: We are dealing with Samaritans, not with Jews. Doesn’t this apply to everyone?? Wasn’t it taught in a baraita to the contrary? As it was taught: Two brothers may bathe together. However, the custom was that two brothers do not bathe together in the city of Kabul. And there was an incident involving Yehuda and Hillel, sons of Rabban Gamliel, who bathed together in Kabul, and the entire city denounced them and said: In all our days we have never seen that type of conduct. Hillel stole away and went out to the outer chamber and did not want to tell them: You are permitted to do so.

Similarly, one may go out with kurdakison, wide shoes (זאקקען or אונטערשוה) on Shabbat; however, one does not go out with wide shoes in the city of Birei. And there was an incident involving Yehuda and Hillel, sons of Rabban Gamliel, who went out with wide shoes in Birei, and the people of the city denounced them and said: In all our days we have never seen that type of conduct. And Yehuda and Hillel removed their shoes, and gave them to their servants, and did not want to tell the residents of the city: You are permitted to go out with wide shoes on Shabbat.

.

Similarly, one may sit on gentiles’ stools on Shabbat, But one may not sit on gentiles' stools on Shabbat in the city of Akko. And there was an incident involving Rabban Shimon ben Gamliel who sat on gentiles’ stools on Shabbat in the city of Akko, and the entire city denounced him. They said: In all our days we have never seen that type of conduct. Rabban Shimon ben Gamliel moved onto the ground and did not want to tell them: You are permitted to sit on the stools.

The legal status of people in the cities since Sages are not found among them, is like that of the Samaritans. Therefore, it is prohibited to tell them that these activities are permitted.

Bishlama, it makes sense that sitting on gentiles’ stools is prohibited because it appears like one is engaged in buying and selling on Shabbat. In the case of wide shoes as well, it could be prohibited to wear them due to the concern lest they fall off one’s feet and one come to carry them in her hand four cubits in the public domain, thereby violating a Torah prohibition.

However, what is the reason that two brothers may not bathe together? It was taught in a baraita: A person may bathe with anyone except for his father, and his father-in-law, and his mother’s husband, and his sister’s husband. And Rabbi Yehuda permits one to bathe with his father, due to the honor that he can accord his father by assisting his father while bathing. The same is true for one’s mother’s husband.

And the people of Kabul came and issued a decree to prohibit bathing together for two brothers, due to their concern that it is similar to bathing with one’s sister’s husband. It was taught in the Tosefta: A student may not bathe with his teacher. But if his teacher requires his help when bathing, it is permitted.

"You are not permitted to permit --"

[Summary:] This is strange.... and Rabbeinu Nissim wrote in a secret scroll that this case is only one where the people knew that the action was permitted but they chose to forbid it to themselves. In such a case, it is forbidden to permit it.

But if they simply made an error in the past and thought that something was forbidden, you may permit it to them!

...And Rabbeinu Yitzhak is unsure in the case of an unimportant tradition, whether:

a) the wise people of the place can have the strict traditions permitted to them, but not the uneducated city-people (who are just like Samaritans),

or b) a visiting scholar can allow themselves not to follow the tradition, but the local people still have to follow it.

.

Transgressing a Custom requires Hatarah, Release.

1) Things which are well-known to be allowed, but the custom is to treat them as forbidden - it is as if one has taken upon themselves a vow, and it is forbidden to release someone from such a practice. Therefore, one who is accustomed to fast before Rosh Hashanah, or between Rosh Hashanah and Yom Kippur; or one who is accustomed to refrain from meat between the 17th of Tammuz and the 9th of Av, and wants to change their custom for health reasons - they need to come before a court of three who will release them from their vow.... therefore somebody who wishes to start a new strict custom should declare at first that this is not a vow...

Those who make a mistake don't need to be released from a vow. But if one knows that it was permitted and still treated it as forbidden, there are those who say that this becomes like a law of the Torah, and one can not be released from this vow ever.

(RAMA, Ashkenazi footnote: We don't follow this last opinion.)

2) A practice accepted by an entire community remains with them and their children, even if the children never accepted it. This is even the case when a city accepts a custom without being instructed by a rabbi. Those who visit them from outside the city have to take on their strict practice, as well as the strict practices of the city they left.