Leviticus 23:33-36

Then the LORD spoke to Moses, saying, “Speak to the children of Israel, saying: ‘The fifteenth day of this seventh month shall be the Feast of Tabernacles for seven days to the LORD. On the first day there shall be a holy convocation. You shall do no customary work on it. For seven days you shall offer an offering made by fire to the LORD. On the eighth day you shall have a holy convocation, and you shall offer an offering made by fire to the LORD. It is a sacred assembly, and you shall do no customary work on it.