'Voluntary offerings' in the Bible

and thither ye shall bring your burnt-offerings and your sacrifices, and your tithes, and the heave-offering of your hand, and your vows, and your voluntary-offerings, and the firstlings of your kine and of your sheep;

Thou mayest not eat within thy gates the tithe of thy corn, or of thy new wine, or of thine oil, or the firstlings of thy kine or of thy sheep, nor any of thy vows which thou vowest, nor thy voluntary-offerings, nor the heave-offering of thy hand;