Deuteronomy 16:10 And you shall keep the feast of weeks to the LORD your God with a tribute of a freewill offering of your hand, which you shall give to the LORD your God, according as the LORD your God has blessed you: Nave's Topical Index
Deuteronomy 23:23 That which is gone out of your lips you shall keep and perform; even a freewill offering, according as you have vowed to the LORD your God, which you have promised with your mouth. Nave's Topical Index