Who is of a willing Heart?

1 Chronicles 29:9-11 KJV Then the people rejoiced, for that they offered willingly, because with perfect heart they offered willingly to the Lord : and David the king also rejoiced with great joy. [10] Wherefore David blessed the Lord before all the congregation: and David said, Blessed be thou, Lord God of Israel our father, for ever and ever. [11] Thine, O Lord , is the greatness, and the power, and the glory, and the victory, and the majesty: for all that is in the heaven and in the earth is thine ; thine is the kingdom, O Lord , and thou art exalted as head above all.