'Voluntary' in the Bible

If his offering be a burnt sacrifice of the herd, let him offer a male without blemish: he shall offer it of his own voluntary will at the door of the tabernacle of the congregation before the LORD.

But if the sacrifice of his offering be a vow, or a voluntary offering, it shall be eaten the same day that he offereth his sacrifice: and on the morrow also the remainder of it shall be eaten:

Speak unto Aaron, and to his sons, and unto all the children of Israel, and say unto them, Whatever man of the house of Israel, or of the sojourners in Israel, that presenteth his offering for any of his vows, and for any of his voluntary offerings, which they present to Jehovah as a burnt-offering,

And if any present a sacrifice of peace-offering to Jehovah to accomplish a vow, or a voluntary offering of oxen or small cattle, it shall be without blemish to be accepted: there shall be no defect therein.

A bullock and a sheep that hath a member too long or too short, that mayest thou offer as a voluntary offering; but as a vow it shall not be accepted.

besides the sabbaths of Jehovah, and besides your gifts, and besides all your vows, and besides all your voluntary offerings, which ye give to Jehovah.