'Voluntary offerings' in the Bible

These shall ye offer to Jehovah in your set feasts, besides your vows, and your voluntary-offerings, for your burnt-offerings, and for your oblations, and for your drink-offerings, and for your peace-offerings.

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;

And Kore the son of Jimnah the Levite, the doorkeeper toward the east, was over the voluntary-offerings of God, to distribute the heave-offerings of Jehovah, and the most holy things.

Accept, I beseech thee, Jehovah, the voluntary-offerings of my mouth, and teach me thy judgments.