Leviticus 23:41-43

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.’”