Deuteronomy 16:13-17

13Thou shalt observe the feast of tabernacles seven days, after that thou hast gathered in thy threshingfloor and thy wine:1 14And thou shalt rejoice in thy feast, thou, and thy son, and thy daughter, and thy manservant, and thy maidservant, and the Levite, the stranger, and the fatherless, and the widow, that are within thy gates. 15Seven days shalt thou keep a solemn feast unto Yhwh thy God in the place which Yhwh shall choose: because Yhwh thy God shall bless thee in all thine increase, and in all the works of thine hands, therefore thou shalt surely rejoice.

16Three times in a year shall all thy males appear before Yhwh 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 Yhwh empty: 17Every man shall give as he is able, according to the blessing of Yhwh thy God which he hath given thee.2