וְרׇחְבָּן שִׁשָּׁה and their width is six handbreadths.
רַבִּי שִׁמְעוֹן אוֹמֵר עוֹשֶׂה תּוֹכָהּ שֶׁל מְעָרָה שֵׁשׁ אַמּוֹת עַל שְׁמוֹנֶה וּפוֹתֵחַ לְתוֹכָהּ שְׁלֹשָׁה עָשָׂר כּוּךְ אַרְבָּעָה מִכָּאן וְאַרְבָּעָה מִכָּאן וּשְׁלֹשָׁה מִכְּנֶגְדָּן וְאֶחָד מִימִין הַפֶּתַח וְאֶחָד מִן הַשְּׂמֹאל Rabbi Shimon says: He should construct the inside of each burial chamber six cubits wide by eight cubits long and open up into the chamber, by digging into its walls, thirteen burial niches. Four niches should be opened up from the wall here, along the length of the chamber, and four from there, along the other side, and three niches from the wall facing the entrance, and one from the right of the entrance and another one from the left.
וְעוֹשֶׂה חָצֵר עַל פִּי הַמְּעָרָה שֵׁשׁ עַל שֵׁשׁ כִּמְלֹא הַמִּטָּה וְקוֹבְרֶיהָ The mishna describes the general structure of the catacomb: And he must fashion a courtyard at the entrance of the burial chamber that should be six cubits by six cubits, which is equal to the combined length of the bier of the deceased and those who bury him, to ensure adequate room for the burial to take place.
וּפוֹתֵחַ לְתוֹכָהּ שְׁתֵּי מְעָרוֹת אַחַת מִכָּאן וְאַחַת מִכָּאן רַבִּי שִׁמְעוֹן אוֹמֵר אַרְבַּע לְאַרְבַּע רוּחוֹתֶיהָ And he should open up two burial chambers into the courtyard, one from here and one from there, i.e., on opposite sides of the courtyard. Rabbi Shimon says: He should open up four burial chambers, one on each of the courtyard’s four sides.
רַבָּן שִׁמְעוֹן בֶּן גַּמְלִיאֵל אוֹמֵר הַכֹּל לְפִי הַסֶּלַע: Rabban Shimon ben Gamliel says: Everything is dependent on the nature of the bedrock. If the bedrock is hard and strong it will be able to accommodate more niches, which will be more closely packed together, with less bedrock between them. If the bedrock is softer, fewer and more sparsely spaced niches should be formed.
גְּמָ׳ הָנֵי תְּרֵי לְהֵיכָא שָׁדֵי לְהוּ אִי לְבָרַאי הָא קָמִיתַּדְשִׁי לְהוּ וְתוּ הָא תְּנַן חֲצַר הַקֶּבֶר הָעוֹמֵד בְּתוֹכוֹ טָהוֹר GEMARA: In Rabbi Shimon’s depiction of a burial chamber, he states that two niches should be opened up, one from the right of the entrance and one from the left. The Gemara asks: These two niches, in which direction does he set them? If they are directed toward the outside of the chamber, i.e., under the floor of the courtyard, won’t people trample over them when they enter the courtyard, which is improper? And furthermore, didn’t we learn in the mishna (Oholot 15:8): With regard to the courtyard of a catacomb, one who stands inside it is ritually pure because it can be presumed that he did not stand over a dead body? Clearly, these niches are not to be dug underneath the courtyard.
אָמַר רַבִּי יוֹסֵי בְּרַבִּי חֲנִינָא דְּעָבֵיד לְהוּ כְּמִין נֶגֶר Rabbi Yosei, son of Rabbi Ḥanina, said: He makes these two niches at the side of the entrance, vertically, like a door bolt.
וְהָא אָמַר רַבִּי יוֹחָנָן The Gemara challenges this explanation: But doesn’t Rabbi Yoḥanan say with regard to the burial of people in a vertical position: