Leviticus 23:37-39

Amplified Bible

³⁷ ‘These are the appointed times (established feasts) of the Lord, which you shall proclaim to be holy convocations, to present an offering by fire to the Lord, a burnt offering and a grain offering, sacrifices and drink offerings, each on its own day. ³⁸ This is in addition to the [weekly] Sabbaths of the Lord, and in addition to your gifts and all your vowed offerings and all your freewill offerings, which you give to the Lord.

³⁹ ‘On exactly the fifteenth day of the seventh month (nearly October), when you have gathered in the crops of the land, you shall celebrate the feast of the Lord for seven days, with a Sabbath rest on the first day and a Sabbath rest on the eighth day.