Deuteronomy 16:13-15

After you have finished the grain harvest and the grape harvest, take your sons and daughters and all your servants to the place where the LORD chooses to be worshipped. Celebrate the Festival of Shelters for seven days. Also invite the poor, including Levites, foreigners, orphans, and widows. The LORD will give you big harvests and make you successful in everything you do. You will be completely happy, so celebrate this festival in honour of the LORD your God.