Deuteronomy 16:10-11

16:10 Then you are to celebrate the Festival of Weeks before the Lord your God with the voluntary offering that you will bring, in proportion to how he has blessed you. 16:11 You shall rejoice before him – you, your son, your daughter, your male and female slaves, the Levites in your villages, the resident foreigners, the orphans, and the widows among you – in the place where the Lord chooses to locate his name.