'Willingly' in the Bible

And the chief fathers and princes of the tribes of Israel, and the captains of thousands and of hundreds, and the comptrollers of the king's business, offered willingly.

And the people rejoiced because they offered willingly, for with perfect heart they offered willingly to Jehovah; and David the king also rejoiced with great joy.

But who am I, and what is my people, that we should be able to offer willingly after this manner? for all is of thee, and of that which is from thy hand have we given thee.

And I know, my God, that thou triest the heart, and hast pleasure in uprightness. In the uprightness of my heart have I willingly offered all these things; and now have I seen with joy thy people, which are present here, offer willingly to thee.