Deuteronomy 16:13-17

Celebrate the Feast of Shelters for seven days, after you have gathered your harvest from the threshing floor and winepress. Everybody should rejoice at your Feast: you, your sons and daughters, your male and female servants, the Levites, strangers, orphans, and widows who live in your towns. Celebrate the Feast to the LORD your God for seven days at the place he will choose, because the LORD your God will bless all your harvest and all the work you do, and you will be completely happy. All your men must come before the LORD three times a year to the place he will choose. They must come at these times: the Feast of Unleavened Bread, the Feast of Weeks, and the Feast of Shelters. No man should come before the LORD without a gift. Each of you must bring a gift that will show how much the LORD your God has blessed you.