In our earlier post on Eruvin 74-75, we discussed the situation where a community had received a lenient ruling which it followed and was later given a more stringent ruling by a new authority.

We noted the ruling of the Rema that a new Rav may indeed repeal the lenient ruling of a previous Rav, and that this might also apply to repealing an earlier stringent ruling.

The later might be more problematic, given the general rule (Pesachim 51a ) that דברים המותרים ואחרים נהגו בהם אסור אי אתה רשאי להתירן לפניהם  – things that are permitted but others were accustomed to forbid, one is not permitted to permit in front of them.

If this is the case for a stringency that a community took on by itself, how much more so should it be the case for something which they took on because of a ruling from their previous Rav!

In our Misha at the bottom of Eruvin 101, there is an explicit reference to a similar situation where Rabbis repealed existing lenient or stringent practices, though it is not clear whether the original practise was based on an earlier ruling of a Torah scholar, or simply developed over time.

The mishna continues to discuss actions that might resemble the מלאכה  of building on shabbos, including inserting a bolt whose one head is large enough to use to pound food (and thus considered a useful vessel already ) into a door in order to lock it (I have followed Rashi’s explanation here for the sake of brevity but this is a complex discussion in the Rishonim in its own right.)

The  Gemara later makes clear that if the bolt is already permanently connected to the door and is easily moved without the rope breaking (see Rashi and other Rishonim who give different explanations) even Rabbi Eliezer permits locking the door with it, as doing so no longer resembles building.

In contrast, if it was already connected to the door, but cannot be moved without the rope breaking (once again following Rashi’s explanation) , Rabbi Eliezer forbids doing so, seeing as it is not properly connected already, whereas Rabbi Yossi permits, seeing as it already has the features of a useful כלי and doing so does not resemble building.

The Ritva explains that this is because a person does not usually permanently set aside a useful כלי  as a bolt and it is clear to all that this is only a temporary fix and not an act of building .

Fascinatingly, both Rabbi Eliezer and Rabbi Yossi bring support for their view from an incident in the shul in Teverya.

Rabbi Eliezer reported that the original custom in that shul was to lock the door with such a bolt, and when Rabban Gamliel and the elders came, they forbade it.

In contrast, Rabbi Yossi accounts that the original custom had been not to do so, and that when Rabban Gamliel and the elders came, they permitted it!

Although they do not appear bothered at all by the fact that according to Rabbi Eliezer, Rabban Gamliel and the elders forbade something against the existing custom to permit it, Tosfos are bothered by how according to Rabbi Yossi, they permitted something against the existing custom to forbid it.

This is because , as mentioned above, we have learnt (Pesachim 51a) that if something is permitted but others have treated it as forbidden, it is forbidden to permit it in front of them.

Seeing as the member of that shul were long accustomed to prohibiting this, how could Rabban Gamliel and the elders come and permit it?

Their answer could have  far-reaching ramifications for the authority of minhagim in general, and we shall hopefully get the chance soon again in Pesachim to discuss this issue in more detail.

For our purposes, we shall note that Tosfos distinguishes between a custom which people took on because they mistakenly believed something was actually forbidden, and a custom which people took on as an extra chumra despite knowing that it was actually permitted.

In the former case, their minhag was taken on due to error, and one may certainly permit it to them.

In the later case, no error was involved, and one may not later permit it.

Tosfos understands that according to Rabbi Yosi, the members of the shul refrained from locking the door with such a bolt because they mistakenly believed it was forbidden, and Rabban Gamliel and the elders were well within their rights to correct their error and permit it!

What is still unclear is what the reason was for their initial error? Was it simply ignorance on their part, or was it because another Rabbi had mistakenly (at least in the view of the later Rabbi) told them that it was forbidden (as Rabbi Eliezer indeed held?)

If the later is true, it would solve our original problem of how a new Rabbi can permit something forbidden by the previous Rabbi if in his view, the previous Rabbi was wrong.

It is also possible, however, that seeing as the community was doing the right thing by following their Rabbi at the time, their stringent practise cannot be seen as an error, and in such a case, the new Rabbi may not permit it.

The role of rabbinic authority in the acceptance of minhagim is itself worthy of much discussion, and as mentioned, I hope to continue this when we reach the relevant sugya in Pesachim, Hashem willing!

These posts are intended to raise issues and stimulate further research and discussion on contemporary topics related to the daf. They are not intended as psak halacha