Ezr 7:13 I make a decree, that all they of the people of Israel, and of his priests and Levites, in my realm, which are minded of their own freewill to go up to Jerusalem, go with thee.
Lev 22:18 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;
Lev 22:21 And whosoever offereth a sacrifice of peace offerings unto the LORD to accomplish his vow, or a freewill offering in beeves or sheep, it shall be perfect to be accepted; there shall be no blemish therein.
Lev 22:23 Either a bullock or a lamb that hath any thing superfluous or lacking in his parts, that mayest thou offer for a freewill offering; but for a vow it shall not be accepted.
Num 15:3 And will make an offering by fire unto the LORD, a burnt offering, or a sacrifice in performing a vow, or in a freewill offering, or in your solemn feasts, to make a sweet savour unto the LORD, of the herd, or of the flock:
Psa 119:108 Accept, I beseech thee, the freewill offerings of my mouth, O LORD, and teach me thy judgments.
Rev 22:17 And the Spirit and the bride say, Come. And let him that heareth say, Come. And let him that is athirst come. And whosoever will, let him take the water of life freely. (Don't give me that rubbish about a sign over Heaven's gate)