Leviticus 23:38-43

38besides the Sabbaths of the Lord and all your gifts, votive offerings, and freewill offerings which you must give to the Lord.

39“‘On the fifteenth day of the seventh month, when you gather in the produce of the land, you must celebrate a pilgrim festival of the Lord for seven days. On the first day is a complete rest and on the eighth day is complete rest.

40On the first day you must take for yourselves branches from majestic trees – palm branches, branches of leafy trees, and willows of the brook – and you must rejoice before the Lord your God for seven days.

41You must celebrate it as a pilgrim festival to the Lord for seven days in the year. This is a perpetual statute throughout your generations; you must celebrate it in the seventh month.

42You must live in temporary shelters for seven days; every native citizen in Israel must live in temporary shelters,

43so that your future generations may know that I made the Israelites live in temporary shelters when I brought them out from the land of Egypt. I am the Lord your God.’”