"Speak to the people of Israel, saying, In the seventh month, on the first day of the month, you shall observe a day of solemn rest, a memorial proclaimed with blast of trumpets, a holy convocation.” -Leviticus 23:24
Now on the tenth day of this seventh month is the Day of Atonement. It shall be for you a time of holy convocation, and you shall afflict yourselves and present a food offering to the LORD. -Leviticus 23:27
You will dwell in booths for seven days. All native Israelites will dwell in booths, that your generations may know that I made the people of Israel dwell in booths when I brought them out of the land of Egypt: I am the Lord your God. -Leviticus 23:42-43