Leviticus 23:40-43

And you shall take on the first day the fruit of splendid trees, branches of palm trees and boughs of leafy trees and willows of the brook, and you shall rejoice before the LORD your God seven days. You shall celebrate it as a feast to the LORD for seven days in the year. It is a statute forever throughout your generations; you shall celebrate it in the seventh month. You shall dwell in booths for seven days. All native Israelites shall dwell in booths, that your generations may know that I made the people of Israel dwell in booths when I brought them out of the land of Egypt: I am the LORD your God.”