Only four days after Yom haKippurim we find ourselves in the midst of another holiday, Sukkoth. The popular compendium Séfer haToda‘ah by Rabbi Eliyahu Kitov notes that Sukkoth involves more discrete mitzvoth than any other holiday, and suggests that it follows so closely on Yom Kippur because, having been (we profoundly hope) exonerated fom any sins of the past, G-d wants us now to be so engaged in preparations for perfomance of a pack of mitzvoth that we barely have time to sin, while piling up the merits of observance.
The holiday is named for one of the central mitzvoth, that of living, or at least taking our meals in, a temporary hut called a sukka. The walls of the hut can be constructed from any sort of material, but the roof must be covered with sëchach, a thatch made of plant material which is nonetheless open to the sky somewhat; the Talmudic formulation is that tzillëthah mërubba méchamathah (“its shade is greater than its sunlight”), though there must also be some sunlight poking though.
The written Torah describes this mitzva in Leviticus XXIII,42-43: Bësukkoth téshëvu shiv‘ath yamim kol ha’ezrach miYisra’él yéshëvu bësukkoth lëma‘an yédë‘u dorotheichem ki bësukkoth hoshavti eth bënei Yisra’él bëhotzi’i otham mé’eretz Mitzrayim (“In sukkoth you will dwell seven days; every citizen of Israel will dwell in sukkoth in order that your generations will know that in sukkoth I settled the bënei Yisra’él when I brought them out of the land of Egypt.”)
There are two views, the Talmud tells us, of what it meant that Ha-Shem “settled the bënei Yisra’él in sukkoth” on their way out of Egypt: “It is taught: Rabbi Eli‘ezer says, Just as a man may not fulfill his duty on the first day of the holiday with his fellow’s lulav, for it is written: ‘And you will take for yourselves on the first day [of Sukkoth] the fruit of a splendid tree, tops of palms’ (Leviticus XXIII,40), i.e. of your own, so does he not fulfill his duty with his fellow’s sukka, for it is written: ‘The holiday of Sukkoth you will make for yourselves seven days’ (Deuteronomy XVI,13) – i.e. your own. And the [other] Rabbis say, Even though we have said that a man does not fulfill his duty on the first day of the holiday with his fellow’s lulav, he still does fulfill his duty with his fellow’s sukka, for it is written, ‘every citizen of Israel will dwell in sukkoth,’ teaching that all of Israel are fit to sit in one sukka” (Sukka 27b).
As Rashi explains the issue, the last statement implies a single sukka in which people would sit in relays, one after the other, taking “ownership” of the sukka from his predecessor by “borrowing” it.