'Freewill Offerings' in the Bible

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

Beside the sabbaths of the LORD, and beside your gifts, and beside all your vows, and beside all your freewill offerings, which ye give unto the LORD.