Deuteronomy 16:13-16

13Celebrate the Festival of Tabernacles for seven days after you have gathered the produce of your threshing floor and your winepress. 14Be joyful at your festival—you, your sons and daughters, your male and female servants, and the Levites, the foreigners, the fatherless and the widows who live in your towns. 15For seven days celebrate the festival to the Lord your God at the place the Lord will choose. For the Lord your God will bless you in all your harvest and in all the work of your hands, and your joy will be complete. 16Three times a year all your men must appear before the Lord your God at the place he will choose: at the Festival of Unleavened Bread, the Festival of Weeks and the Festival of Tabernacles. No one should appear before the Lord empty-handed: