Leviticus 23:42

40And ye shall take you on the first day the boughs of goodly trees, branches of palm trees, and the boughs of thick trees, and willows of the brook; and ye shall rejoice before the LORD your God seven days.

41And ye shall keep it a feast unto the LORD seven days in the year. It shall be a statute for ever in your generations: ye shall celebrate it in the seventh month.

42Ye shall dwell in booths seven days; all that are Israelites born shall dwell in booths:

43That your generations may know that I made the children of Israel to dwell in booths, when I brought them out of the land of Egypt: I am the LORD your God.

44And Moses declared unto the children of Israel the feasts of the LORD.