'Free will' in the Bible

Speak unto Aaron, and to his sons, and unto all the children of Israel, and say unto them, Whosoever he be of the house of Israel, or of the strangers in Israel, that will offer his offering for all his vows, and for all his freewill offerings, which they will offer unto the LORD for a burnt offering;

You shall offer of your own free will a male without blemish, of the cattle, of the sheep, or of the goats.

And whosoever offers a sacrifice of peace offerings unto the LORD to accomplish his vow, or a freewill offering in cattle or sheep, it shall be perfect to be accepted; there shall be no blemish in it.

Either a bullock or a lamb that has any limb too long or too short, that may you offer for a freewill offering; but for a vow it shall not be accepted.

Besides the sabbaths of the LORD, and besides your gifts, and besides all your vows, and besides all your freewill offerings, which you give unto the LORD.