MISHNA: With regard to the door to a rear court, i.e., a door that opens from a house to the courtyard situated behind it, which is typically not a proper door but merely a wooden board without hinges that closes off the doorway; and likewise bundles of thorns that seal a breach; and reed mats, one may not close an opening with them on Shabbat. This would be considered building or completing a building, unless they remain above the ground even when they are open.

GEMARA: And the Gemara raises a contradiction from a baraita: With regard to a door, or a mat, or a lattice [kankan] that drag along the ground and are used for closing up openings, when they are tied and suspended in place one may close an opening with them on Shabbat; and needless to say this is permitted on a Festival. According to the baraita, the critical factor is apparently that they must be tied and suspended, not that they have to be held up above the ground.

Abaye said: The baraita is referring to ones that have a hinge. As they are considered proper doors, closing them does not appear like building. Rava said: The baraita is referring even to doors that once had a hinge, even though they no longer have one. These partitions also bear the clear form of a door, and therefore one’s action does not have the appearance of building.

The Gemara raises an objection from another baraita: With regard to a door, or a mat, or a lattice that drag along the ground, when they are tied and suspended in place and they are held above the ground even by as little as a hairbreadth, one may close an opening with them. However, if they are not raised in this manner, one may not close an opening with them. Clearly, these doors must indeed be raised above the ground as well.

The Gemara answers: Abaye reconciles the objection in accordance with his reasoning, and Rava reconciles the objection in accordance with his reasoning. The Gemara elaborates: Abaye reconciles the objection in accordance with his reasoning by adding to the baraita: They must either have a hinge or be held above the ground. Rava likewise reconciles the objection in accordance with his reasoning, as he reads: They must have had a hinge or else be held above the ground.

The Sages taught a baraita: With regard to branches of thorn bushes or bundles of wood that were arranged so that they sealed off a breach in a courtyard, when they are tied and suspended in place, one may close an opening with them on Shabbat; and needless to say, this is permitted on a Festival.

Rabbi Ḥiyya taught a baraita: With regard to a widowed door that drags along the ground, one may not close an opening with it. The Gemara asks: What are the circumstances of a widowed door? Some say it refers to a door built from a single plank, which does not look like a door, and others say it is a door that does not have a lower doorsill (ge’onim) and that touches the ground when closed.

With regard to activities that are prohibited because of their similarity to building, the Gemara cites a teaching that Rav Yehuda said: When arranging a pile of wood for a fire on a Festival, if the logs are arranged from the top down, i.e., the upper logs are temporarily suspended in the air while the lower logs are inserted below them, it is permitted. However, if the wood is placed from the bottom up, it is prohibited, as the arrangement of wood in the regular manner is a form of building.

And the same applies to eggs that are to be arranged in a pile, and the same applies to a cauldron that is to be set down on a fire by means of supports, and the same applies to a bed that will be placed on its frame, and the same applies to barrels arranged in a cellar. In all these cases, the part that goes on top must be temporarily suspended in the air while the lower section is inserted beneath it.

With regard to bundles of thorns used to seal a breach, the Gemara cites a related incident: A certain heretic once said to Rabbi Yehoshua ben Ḥananya: Man of thorns! For it says about you: “The best of them is as a brier” (Micah 7:4), which indicates that even Israel’s best are merely thorns. He said to him: Fool, go down to the end of the verse: “The most upright is worse than a thorn hedge,” a derogatory expression meant as praise. Rather, what is the meaning of the best of them is as a brier? It means that just as these thorns protect a breach, so the best among us protect us. Alternatively: The best of them is as a brier [ḥedek] means that they grind [mehaddekin] the nations of the world into Gehenna, as it is stated: “Arise and thresh, O daughter of Zion, for I will make your horn iron, and I will make your hoofs brass, and you shall beat in pieces [vahadikot] many peoples; and you shall devote their gain to God, and their substance to the God of the whole earth” (Micah 4:13).

MISHNA: A person may not stand in the private domain and open a door located in the public domain with a key, lest he inadvertently transfer the key from one domain to the other. Likewise, one may not stand in the public domain and open a door in the private domain with a key, unless in the latter case 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: There was an incident at the poultry dealers’ market in Jerusalem, where they would fatten fowl for slaughter (Rabbeinu Ḥananel), and they would lock the doors to their shops and place the key in the window that was over the door, which was more than ten handbreadths off the ground, and nobody was concerned about the possible violation of any prohibition. Rabbi Yosei says: That place was a market of wool dealers.

GEMARA: The Gemara asks: And those Rabbis, who cited the case of the poultry dealers of Jerusalem to rebut Rabbi Meir’s opinion, Rabbi Meir spoke to them about unlocking a door in a private domain while standing in the public domain, and they responded with an incident involving a karmelit. As Rabba bar bar Ḥana said that Rabbi Yoḥanan said: With regard to Jerusalem, were it not for the fact that its doors are locked at night, one would be liable for carrying in it on Shabbat, because its thoroughfares have the status of the public domain. However, since Jerusalem’s doors are typically locked, it is considered one large karmelit, which is subject to rabbinic prohibitions. How, then, could a proof be cited from the markets of Jerusalem with regard to the transfer of objects between a public domain and a private domain, which is prohibited by Torah law?

Rav Pappa said: Here, in the statement of Rabbi Yohanan, Jerusalem was considered a karmelit during the period before breaches were made in its walls. Its doors did not turn it into a public domain, as they were locked. Whereas there, the Rabbis in the mishna are referring to the time after breaches had been made in the walls, and it therefore acquired the status of a public domain.

Rava said: In the latter clause of the mishna we came to a different issue, i.e., the final section of the mishna is not designed to counter Rabbi Meir’s statement with regard to the public domain. Rather, it refers to the gates of a garden with an area greater than two beit se’a in size, whose legal status is that of a karmelit. Consequently, the mishna is saying as follows: And likewise, one may not stand in the private domain and open a door in a karmelit; neither may one stand in a karmelit and open a door in the private domain,