Deuteronomy 16:9-12 - The Festival Of Weeks
9 "Count off seven weeks from when the sickle is first put to standing grain. 10 Then observe the Festival of Weeks in the presence of the LORD your God by giving your tribute and the freewill offering of your hands in proportion to the manner in which the LORD your God blessed you. 11 Rejoice in the presence of the LORD your God with your son, daughter, male and female slaves, the descendants of Levi who is in your city, the stranger, the orphan, and the widow among you, at the place where the LORD your God will choose to establish his name. 12 Remember that you were slaves in Egypt, so keep and observe these statutes."