Talmud - Eruvin 43a עירובין מ״ג א׳

for they are only made to keep the water out; that is to say, a boat’s walls are not designed to turn it into a place of residence, but to protect it from the water. Therefore, they do not have the status of partitions made for the purpose of residence.

The Gemara asks: As for Rabba, what is the reason he did not state his opinion in accordance with the opinion of Rabbi Zeira? The Gemara answers: With regard to a boat that is moving, all agree, i.e., even Rabbi Yehoshua and Rabbi Akiva, that one is permitted to walk about the entire boat. They disagree only with regard to a boat that is stationary. Rabban Gamliel holds that the boat’s walls constitute effective partitions, whereas Rabbi Yehoshua disagrees.

Rav Naḥman bar Yitzḥak said: The mishna is also precise in its implication that the tanna’im do not disagree with regard to a moving boat. The Gemara asks: From where is this implied? From that which is taught: There was an incident where all of these Sages were coming from Pelandarsin, and their boat set sail on the sea on Shabbat, taking them out beyond their Shabbat limit. Rabban Gamliel and Rabbi Elazar ben Azarya walked about the entire boat, while Rabbi Yehoshua and Rabbi Akiva did not move beyond four cubits, as they sought to be stringent with themselves.

Rav Naḥman bar Yitzḥak explains: Granted, if you say that they do not disagree with regard to a moving boat, that is why it is taught that they sought to be stringent with themselves, i.e., they wished to practice stringency although they were under no obligation to do so, as they were concerned that perhaps the boat will stand, i.e., come to a stop.

But if you say that they disagree even in the case of a boat that is moving, this phrase: Sought to be stringent, is problematic, for the mishna should not refer to a desire to be stringent, as according to their opinion it is an outright prohibition.

With regard to the previous issue, Rav Ashi said: The mishna is also precise, implying this point in another manner as well, for it teaches the law governing a boat parallel to the law governing a pen and a stable. Just as a pen and a stable are fixed in their place, so too, the mishna discusses a boat that is fixed in its place.

Rav Aḥa, son of Rava, said to Rav Ashi: Rav and Shmuel both said that the halakha is in accordance with Rabban Gamliel with regard to a boat, and if they had to decide the halakha, then this proves by inference that the tanna’im disagreed about the issue. This is difficult, as the words: They wished to be stringent upon themselves, imply that there was no fundamental dispute at all.

Rav Ashi replied: Yes, the tanna’im do in fact disagree about a boat that is standing. When the mishna says that Rabbi Yehoshua and Rabbi Akiva wished to be stringent upon themselves, implying that there is no real dispute, it is referring to a boat that is stationary. And it was taught in a baraita: Ḥananya, son of Rabbi Yehoshua’s brother, says: All that day they spent on the boat, they sat and discussed the matter of halakha; and come evening my father’s brother, i.e., Rabbi Yehoshua, determined: The halakha is in accordance with the opinion of Rabban Gamliel with regard to a moving boat, i.e., one is permitted to walk about all of it. And the halakha is in accordance with the opinion of Rabbi Akiva with regard to a pen and a stable, i.e., one may only walk four cubits in them, and the same applies to a stationary boat.

Rav Ḥananya raised a dilemma: Does the prohibition of Shabbat limits apply above ten handbreadths from the ground, or perhaps does the prohibition of Shabbat limits not apply above ten handbreadths? In other words, does the Shabbat limit apply only close to the ground, in which case walking more than ten handbreadths above the ground, would be permitted?

The Gemara clarifies the case in which this dilemma arises: With regard to a post ten handbreadths high and four handbreadths wide, partly within the limit and partly outside of it, this case should not be a dilemma for you. Such a stable post is like solid ground, although it differs from the surrounding area in height; therefore, it is prohibited to walk from the part within the limit to the part outside of it.

The case where there should be a dilemma for you is that of a post ten handbreadths high but not four handbreadths wide, or the like. Alternatively, the case is one where he advances by way of a leap in the air above ten handbreadths from the ground.

The Gemara presents another version of the previous dilemma: What is the halakha with regard to a boat sailing on the surface of the water more than ten handbreadths from the sea or river bed? Does the prohibition of Shabbat limits apply or not?

Rav Hoshaya said: Come and hear a resolution to this dilemma from what was taught in the mishna: It once happened that all of these Sages were coming from Pelandarsin, and their boat set sail on the sea, etc. Granted, if you say that the prohibition of Shabbat limits applies above ten handbreadths, this is why Rabbi Yehoshua and Rabbi Akiva sought to be stringent. However, if you say that the prohibition of Shabbat limits does not apply above ten handbreadths, why did they seek to be stringent?

The Gemara answers: It may be suggested as Rava said with regard to a parallel case, establishing that case as one where the boat was moving through shallow, swampy water; here, too, we are dealing with a case where the boat was moving through shallow, swampy water, within ten handbreadths of the sea’s bed, so that the prohibition of Shabbat limits certainly applies.

The Gemara cites another proof. Come and hear a resolution from the mishna: On one occasion on a Shabbat eve, they did not enter the port until after nightfall, etc. Granted, if you say that the prohibition of Shabbat limits applies above ten handbreadths, it was well that they asked whether or not they may disembark. However, if you say that the prohibition of Shabbat limits does not apply above ten handbreadths, even if Rabban Gamliel had told them: We were not within the city’s limit before nightfall, what difference would it have made? They could have alighted from the boat, for the boat was above ten handbreadths, where the prohibition of Shabbat limits does not apply.

The Gemara answers that Rava said: The mishna refers to a case where the boat was moving through shallow, swampy water within ten handbreadths of the sea’s bed.

The Gemara cites another proof: Come and hear a resolution from the incident involving the seven teachings that were first said on Shabbat morning before Rav Ḥisda in Sura and then repeated toward the conclusion of that Shabbat before Rava in Pumbedita, despite the fact that the distance between them is too great for someone to have traversed it on Shabbat.

Who said those teachings, and delivered them from one place to the other? Was it not Elijah the Prophet, who traveled from Sura to Pumbedita by way of a miraculous leap through the air above ten handbreadths from the ground, who said them? Apparently, the prohibition of Shabbat limits does not apply above ten handbreadths, for Elijah would not have transgressed this prohibition. The Gemara rejects this argument: This is no proof; perhaps Yosef the demon, who does not observe Shabbat, reported these teachings and brought them from Sura to Pumbedita.

The Gemara attempts to bring a different proof: Come and hear that which was taught in a baraita: With regard to one who said: I will be a nazirite on the day that the son of David comes, i.e., upon the arrival of the Messiah, he is permitted to drink wine on Shabbat and Festivals, for the Messiah will not arrive on one of those days.

Traduction : The William Davidson digital edition of the Koren Noé Talmud, with commentary by Rabbi Adin Even-Israel Steinsaltz.

Eruvin 43a explores rabbinic debate over Shabbat boundaries on a moving versus stationary boat and whether its walls count as valid partitions.