'Free will' in the Bible

And there you must take your burnt offerings, your sacrifices, your tithes, the personal offerings you have prepared, your votive offerings, your freewill offerings, and the firstborn of your herds and flocks.

You will not be allowed to eat in your villages your tithe of grain, new wine, olive oil, the firstborn of your herd and flock, any votive offerings you have vowed, or your freewill and personal offerings.

Suppose a Levite comes by his own free will from one of your villages, from any part of Israel where he is living, to the place the Lord chooses

Whatever you vow, you must be careful to do what you have promised, such as what you have vowed to the Lord your God as a freewill offering.