In Leviticus 23: 33-44, we find a description of the Feast of Tabernacles as God commands Moses to explain this celebration to the Israelites, along with other feasts and sacred assemblies.
The Feast of Tabernacles is a harvest festival, and Scripture records: “beginning with the fifteenth day of the seventh month, after you have gathered the crops of the land, celebrate the festival to the Lord for seven days.” (Leviticus 23:39)
The Israelites were to begin and end the 7-8 days with a sacred assembly, and in between, they were to bring offerings and sacrifices to the Lord made by fire.
Even though the first day of the festival was a sacred assembly and rest day, they were directed “to take choice fruit from the trees, and palm fronds, leafy branches and poplars, and rejoice before the Lord for seven days.” (Leviticus 23: 40) They were also directed to “live in booths for seven days” reminiscent of the time when the Lord brought them out of Egypt. (verses 42-43).