Talmud - Eruvin 43b עירובין מ״ג ב׳

However, he is prohibited to drink wine on all weekdays, in case the Messiah has come and he has not yet been informed.

The Gemara clarifies: Granted, if you say that the prohibition of Shabbat limits applies above ten handbreadths, that is why on Shabbat and Festivals he is permitted to drink wine, for the Messiah will certainly not arrive from outside the Shabbat limit on those days. But if you say that the prohibition of Shabbat limits does not apply above ten handbreadths, why is he permitted to drink wine on Shabbat and Festivals?

The Gemara answers: It is different there, as the verse stated: “Behold I will send you Elijah the prophet, before the coming of the great and dreadful day of the Lord; and he shall turn the heart of the fathers to the children, and the heart of the children to their fathers” (Malachi 3:23–24). This verse teaches that Elijah will arrive the day before the coming of the Messiah. Since Elijah did not come the previous day, the Messiah will not come today, and therefore he may drink.

The Gemara rejects this argument: If so, on weekdays, too, he should be permitted to drink wine each and every day, as Elijah did not arrive the previous day. Rather, the reason for the prohibition on weekdays must be that we say that Elijah may already have arrived at the Great Court, but it has not yet become a matter of public knowledge. Likewise, here too we should say that Elijah already arrived the previous day at the Great Court, on the eve of Shabbat or a Festival.

The Gemara answers: It has already been promised to the Jewish people that Elijah will not come either on the eve of Shabbat or on the eve of a Festival, due to the trouble, lest people go out to greet him and not have time to complete all their preparations for the sacred day.

The Gemara comments: It might enter your mind to say that since Elijah will not come on Shabbat eve due to the trouble involved, the Messiah will also not come then, and if so, on Shabbat eve he should also be permitted to drink wine. However, this reasoning is rejected: It is only Elijah who will not arrive on Shabbat eve, but the Messiah himself may arrive, for once the Messiah comes, all the nations will be subservient to the Jewish people, and they will help them prepare whatever is needed for Shabbat.

The Gemara raises a difficulty: He should be permitted to drink wine on a Sunday, for if Elijah cannot come on Shabbat, the Messiah will not come on a Sunday. Let us resolve from here that the prohibition of Shabbat limits does not apply above ten handbreadths, as if the prohibition of Shabbat limits applies above ten handbreadths, on Sunday he should be permitted to drink wine, as Elijah cannot come on Shabbat.

The Gemara answers: This tanna was uncertain whether there is a prohibition of Shabbat limits above ten handbreadths or there is no prohibition of Shabbat limits. Therefore, he ruled stringently in this regard concerning Sunday.

The Gemara poses a question: When did the person who took the vow of naziriteship arise and take his vow? If you say he arose and took his vow on a weekday, since the vow of naziriteship already took effect, how can Shabbat come and annul it? Naziriteship cannot take effect one day and be annulled on the next; rather, once it applies, it remains in effect for the entire period of his vow.

Rather, it must be that he arose on Shabbat and took his vow, or else he arose on a Festival and took his vow, and it is only on that day that he is permitted to drink wine, as the Messiah will not come; but from that day on he is prohibited to drink wine, for once the naziriteship takes effect on a weekday, it remains in effect from that point onwards, even on Shabbat and Festivals.

It was taught in the mishna: On one occasion, they did not enter the port until after nightfall on Shabbat eve, and they asked Rabban Gamliel whether they were permitted to alight from the boat. He told them that they were permitted to alight, for he had been watching, and he knew that they had entered within the city’s limit before nightfall, and therefore they may walk throughout the city.

In order to clarify this issue, the Gemara cites that which was taught in a baraita: Rabban Gamliel had a special tube through which he would look and see a distance of two thousand cubits on land, and also determine a corresponding distance of two thousand cubits at sea.

In general, one who wishes to know the depth of a valley can bring such a tube and look through it, and he will know the depth of the valley.

The Gemara cites another statement with regard to measurements: One who wishes to know the height of a palm tree, but does not want to actually climb the tree to measure it, can measure his own height, and the length of his own shadow, and the length of the shadow of the height of the palm tree, and calculate the proportions, and he will know the height of the palm tree.

The Gemara cites related advice: If, out of honor for the dead, one wishes that a wild beast should not rest in the shade of a grave, he should insert a reed into the ground at the end of the fourth hour of the day, roughly ten o’clock in the morning, when it is hot in the sun and cooler in the shade, and beasts begin to seek shelter in the shade. And he should observe in which direction the shadow of the reed inclines, and then slant the gravestone upwards and downwards until he finds an angle at which it casts no shadow at that hour, and the beasts will not come to rest at the grave during the heat of the day.

The Gemara relates that Neḥemya, son of Rav Ḥanilai, was once so engrossed in his learning that he did not notice that he was going out beyond his Shabbat limit. Rav Ḥisda said to Rav Naḥman: Your student Neḥemya is in distress, as he is outside the Shabbat limit and cannot enter. What can we do for him?

Rav Naḥman said to him: Establish a human partition for him, i.e., people who are permitted to go out there should line up and form human walls, through which he is permitted to walk and thereby reenter the Shabbat limit.

Rav Naḥman bar Yitzḥak sat behind Rava, and Rava sat in the first row before Rav Naḥman. Rav Naḥman bar Yitzḥak said to Rava: What precisely was Rav Ḥisda’s dilemma that he addressed to Rav Naḥman with regard to Neḥemya’s distress?

The Gemara explains: If you say that we are dealing with a case where the space between Neḥemya and the Shabbat limit could be filled with people who had established an eiruv and were permitted to go out beyond the Shabbat limit and establish a human partition for Neḥemya, and then it can be argued that the dilemma that he raised was: Is the halakha in accordance with the opinion of Rabban Gamliel that a person may walk throughout an enclosed area, although he had not established residence there before Shabbat while it was still day, and the same applies to a human partition of this kind;

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

Eruvin 43b explores Shabbat boundary limits through the debate on whether one may drink wine while awaiting news of Elijah's arrival before the Messiah.