Leviticus 23:40
40 And on the first day you shall take for yourselves the foliage of beautiful trees, palm branches and boughs of leafy trees and willows of the brook, and you shall be glad before Yahweh your God for seven days.
Leviticus 23:43
43 so that your generations may know that I had the sons of Israel live in booths when I brought them out from the land of Egypt. I am Yahweh your God.’”