Leviticus 23:41-43

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,

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