'Freewill Offerings' in the Bible

And there you shall bring your burnt offerings, and your sacrifices, and your tithes, and heave offerings of your hand, and your vowed offerings, and your freewill offerings, and the firstlings of your herds and of your flocks:

You may not eat within your gates the tithe of your grain, or of your wine, or of your oil, or the firstlings of your herds or of your flock, nor any of your offerings which you vow, nor your freewill offerings, or heave offering of your hand: