'Willing offerings' in the Bible

'Speak unto Aaron, and unto his sons, and unto all the sons of Israel, and thou hast said unto them, Any man of the house of Israel, or of the sojourners in Israel, who bringeth near his offering, of all his vows, or of all his willing offerings which they bring near to Jehovah for a burnt-offering;

apart from the sabbaths of Jehovah, and apart from your gifts, and apart from all your vows, and apart from all your willing-offerings, which ye give to Jehovah.

And Kore son of Imnah the Levite, the gatekeeper at the east, is over the willing-offerings of God, to give the heave-offering of Jehovah, and the most holy things.