Leviticus 23:38

36Seven days you shall offer an offering made by fire to the LORD. On the eighth day shall be a holy convocation to you. You shall offer an offering made by fire to the LORD. It is a solemn assembly; you shall do no regular work.

37“‘These are the appointed feasts of the LORD which you shall proclaim to be holy convocations, to offer an offering made by fire to the LORD, a burnt offering, a meal offering, a sacrifice, and drink offerings, each on its own day—

38in addition to the Sabbaths of the LORD, and in addition to your gifts, and in addition to all your vows, and in addition to all your free will offerings, which you give to the LORD.

39“‘So on the fifteenth day of the seventh month, when you have gathered in the fruits of the land, you shall keep the feast of the LORD seven days. On the first day shall be a solemn rest, and on the eighth day shall be a solemn rest.

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