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 3voluntary offering of your hand in a proportional amount, which you shall give just as the Lord your God blesses you; 11and you shall 4rejoice before the Lord your God, you, your son and your daughter, and your male and female slaves, and 5the Levite who is in your 6town, and 7the stranger, the 8orphan, and the widow who are in your midst, at the place where the Lord your God chooses to establish His name. 129You shall also remember that you were a slave in Egypt, and you shall be careful and 10comply with these statutes.