Deuteronomy 16:13-17

13The feast of tabernacles shalt thou hold seven days, when thou hast gathered in [the produce] of thy floor and of thy winepress.

14And thou shalt rejoice in thy feast, thou, and thy son, and thy daughter, and thy bondman, and thy handmaid, and the Levite, and the stranger, and the fatherless, and the widow, that are in thy gates.

15Seven days shalt thou hold a feast to Jehovah thy 1God in the place which Jehovah will choose; for Jehovah thy 2God will bless thee in all thy produce, and in all the work of thy hands, and thou shalt be wholly joyful.

16Three times in the year shall all thy males appear before Jehovah thy 3God in the place which he will choose, at the feast of unleavened bread, and at the feast of weeks, and at the feast of tabernacles; and they shall not appear before Jehovah empty:

17each [shall give] according to that which is in his power to give, according to the blessing of Jehovah thy 4God which he hath given thee.