Leviticus 23:38-39

King James Version

³⁸ Beside the sabbaths of the Lord, and beside your gifts, and beside all your vows, and beside all your freewill offerings, which ye give unto the Lord.

³⁹ Also in the fifteenth day of the seventh month, when ye have gathered in the fruit of the land, ye shall keep a feast unto the Lord seven days: on the first day shall be a sabbath, and on the eighth day shall be a sabbath.