Deuteronomy 16:9-12

9“1You shall count seven weeks for yourself; you shall begin to count seven weeks from the time you begin to put the sickle to the standing grain. 10Then you shall 2celebrate 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; 11and you shall 3rejoice before the Lord your God, you and your son and your daughter and your male and female servants and 4the Levite who is in your 5town, and 6the stranger and the 7orphan and the widow who are in your midst, in the place where the Lord your God chooses to establish His name. 128You shall remember that you were a slave in Egypt, and you shall be careful to observe these statutes.