Leviticus 23:33

“And the Lord spake unto Moses, etc.] Concerning the feast of tabernacles here repeated and enlarged upon: saying; as follows.”

“On the fifteenth of the same month the feast of Tabernacles was to be kept to the Lord for seven days: on the first day with a holy meeting and rest from all laborious work, and for seven days with sacrifices, as appointed for every day in Num 29:13-33. Moreover, on the eighth day, i.e., the 22nd of the month, the closing feast was to be observed in the same manner as on the first day ( Lev 23:34-36). The name, "feast of Tabernacles" (booths), is to be explained from the fact, that the Israelites were to dwell in booths made of boughs for the seven days that this festival lasted ( Lev 23:42). עצרת, which is used in Lev 23:36 and Num 29:35 for the eighth day, which terminated the feast of…”