Talmud - Eruvin 101b עירובין ק״א ב׳

unless he erected a partition ten handbreadths high around the door and stands inside it; this is the statement of Rabbi Meir. The Rabbis said to him: An incident occurred at the poultry dealers’ market in Jerusalem, as they would lock the doors to their shops and place the key in a window that was over the door, which was higher than ten handbreadths. Rabbi Yosei says: That place was a market of wool dealers.

The Sages taught a baraita: With regard to the entrances of garden gates that open into a public domain, when they have a gatehouse on the inside, which is a private domain, one may open and close them from within. This is because the lock, which is four handbreadths wide and ten handbreadths high, also constitutes a private domain. Consequently, the key may be passed from the gatehouse to the lock. However, they may not be opened or closed from without, as the key may not be passed from the public domain to the private domain of the lock. If the gatehouse is on the outside, one may open and close the doors from without, as once again both the lock and the gatehouse are private domains. They may not, however, be opened from within, as the key may not be passed from the garden, which is a karmelit, to the lock. If they have a gatehouse from here, from within, and there, from without, one may open and close the doors here and there. If they do not have a gatehouse; neither here nor there, it is prohibited to open or close the doors here and there, as one may not carry the key either in the public domain or in the garden.

And likewise, this is the halakha with regard to stores that open into the public domain: When the lock is below ten handbreadths off the ground, it is in the public domain. In that case, one may bring a key on Shabbat eve and place it on the threshold, whose legal status is that of a karmelit, and the following day he may open and close the door and return the key to the threshold.

And when the lock is above ten handbreadths off the ground, one may bring a key on Shabbat eve and place it in the lock. And the following day he may open and close the door and return the key to its place on top of the lock. This is the statement of Rabbi Meir.

And the Rabbis say: Even when the lock is above ten handbreadths off the ground, one may bring a key on Shabbat eve and place it on the threshold, and the following day he may open and close the door and return the key to its place on the threshold or in the window that is above the door.

However, if the window is four by four handbreadths and ten handbreadths above the ground, its status is that of a private domain, and it is therefore prohibited to place the key in the window, because it would be as though one is transferring the key from one domain, a karmelit, to another private domain.

The Gemara infers: From the fact that it is stated in the baraita: And similarly, stores, this proves by inference that we are dealing with a threshold that is a karmelit, as it would otherwise be prohibited to transfer the key from the threshold to the lock. If so, with regard to this lock, what are the circumstances? If there is not an area of four by four handbreadths in it, it does not have the status of a prohibited domain at all, and it is an exempt domain.

And if it is four by four handbreadths, and therefore a private domain, would the Rabbis say in that case: Even when the lock is above ten handbreadths off the ground, he may bring a key on Shabbat eve and place it in the threshold, and the following day he may open and close the door and return the key to the threshold or to a window above the door? Isn’t he moving an object from a karmelit to the private domain?

Abaye said: Actually, the lock is not four by four handbreadths, but there is enough space in the door surrounding it to carve out a hole that would complete its area to the requisite four handbreadths.

And this is their dispute: Rabbi Meir, who conforms to his standard line of reasoning, maintains that one carves out the space to complete it to four handbreadths. In other words, if a small opening is located in a place large enough for it to be widened, the place is viewed as though it had already been carved out, providing the opening with the larger dimensions. And the Rabbis conform to their standard line of reasoning, as they maintain that one does not carve out the space to complete it to four handbreadths. Consequently, the lock in its present condition is not large enough to constitute a place of significance, and it is therefore regarded as an exempt place.

Rav Beivai bar Abaye said: Learn from this baraita three halakhot: Learn from it that according to Rabbi Meir, we carve out to complete the necessary dimensions. And further learn from it that Rabbi Meir retracted his ruling with regard to garden gates. According to Rava, Rabbi Meir prohibited a man standing in a karmelit from opening a door in a private domain, and yet here he permits a similar case.

And learn from the statement of the Rabbis that the ruling of Rav Dimi is accepted. As when Rav Dimi came to Babylonia from Eretz Israel, he said that Rabbi Yoḥanan said: A place with an area that is less than four by four handbreadths and that is set apart from the surrounding area is an exempt domain with regard to carrying on Shabbat. Consequently, if the domain is located between a public domain and a private domain, it is permitted for both the people in the public domain and for the people in the private domain to adjust the burden onto their shoulders, provided that they do not exchange objects with one another. This ruling, that it is prohibited to exchange articles, is supported by the position of the Rabbis that it is prohibited to transfer the key from the threshold, which is a karmelit, via the lock, an exempt domain, to the private domain of the window, as one may not transfer an object from one prohibited domain to another, even via an exempt domain.

MISHNA: With regard to a bolt that secures a door in place and that has a thick knob [gelustera] at its end, a useful implement for a variety of purposes, the tanna’im disagree whether the bolt has the status of a vessel, and one may therefore close the door with it, or whether it is considered a cross beam, which would mean that doing so is classified as building. Rabbi Eliezer prohibits its use, and Rabbi Yosei permits it.

Rabbi Eliezer said: An incident occurred in a synagogue in Tiberias, where they were accustomed to treat use of this bolt as permitted, until Rabban Gamliel and the Elders came and prohibited it to them. Rabbi Yosei says that the opposite was the case: At first they were accustomed to treat use of this bolt as prohibited, and Rabban Gamliel and the Elders came and permitted it to them.

GEMARA: The Gemara narrows the dispute: If the bolt can be moved by the rope with which it is attached to the door, everyone agrees that it is considered part of the door, and one may secure the door with it. When Rabbi Yosei and Rabbi Eliezer disagree,

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

Eruvin 101b examines Shabbat carrying laws for locks and keys at doorways, gatehouses, and shop entrances based on their height and domain status.