Leviticus 23:40-42

40On the first day you are to take the product of majestic trees — palm fronds, boughs of leafy trees, and willows of the brook  — and rejoice before the Lord your God for seven days.

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

42You are to live in shelters for seven days. All the native-born of Israel must live in shelters,