Deuteronomy 16:10-11

Then you shall celebrate the Feast of Weeks to the LORD your God with a tribute of a freewill offering of your hand, which you shall give just as the LORD your God blesses you; and you shall rejoice before the LORD your God, you and your son and your daughter and your male and female servants and the Levite who is in your town, and the stranger and the orphan and the widow who are in your midst, in the place where the LORD your God chooses to establish His name.