Leviticus 23:37-40

37“‘These are the appointed times of the Lord that you must proclaim as holy assemblies to present a gift to the Lord – burnt offering, grain offering, sacrifice, and drink offerings, each day according to its regulation,

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.