Deuteronomy 16:7-17

7And thou shalt roast and eat it in the place which Jehovah thy God shall choose: and thou shalt turn in the morning, and go unto thy tents. 8Six days thou shalt eat unleavened bread; and on the seventh day shall be a solemn assembly to Jehovah thy God; thou shalt do no work therein.

9Seven weeks shalt thou number unto thee: from the time thou beginnest to put the sickle to the standing grain shalt thou begin to number seven weeks. 10And thou shalt keep the feast of weeks unto Jehovah thy God with a tribute of a freewill-offering of thy hand, which thou shalt give, according as Jehovah thy God blesseth thee: 11and thou shalt rejoice before Jehovah thy God, thou, and thy son, and thy daughter, and thy man-servant, and thy maid-servant, and the Levite that is within thy gates, and the sojourner, and the fatherless, and the widow, that are in the midst of thee, in the place which Jehovah thy God shall choose, to cause his name to dwell there. 12And thou shalt remember that thou wast a bondman in Egypt: and thou shalt observe and do these statutes.

13Thou shalt keep the feast of tabernacles seven days, after that thou hast gathered in from thy threshing-floor and from thy winepress: 14and thou shalt rejoice in thy feast, thou, and thy son, and thy daughter, and thy man-servant, and thy maid-servant, and the Levite, and the sojourner, and the fatherless, and the widow, that are within thy gates. 15Seven days shalt thou keep a feast unto Jehovah thy God in the place which Jehovah shall choose; because Jehovah thy God will bless thee in all thine increase, and in all the work of thy hands, and thou shalt be altogether joyful. 16Three times in a year shall all thy males appear before Jehovah thy God in the place which he shall choose: in the feast of unleavened bread, and in the feast of weeks, and in the feast of tabernacles; and they shall not appear before Jehovah empty: 17every man shall give as he is able, according to the blessing of Jehovah thy God which he hath given thee.