In addition, because I have set my affection on the house of my God, seeing that I have a treasure of my own of gold and silver, I give it to the house of my God, over and above all that I have prepared for the holy house,
So David is, has told of his own commitment and now he's challenging them for a commitment of giving to God. "This is what I have done. This is what I propose to do. Now who of you are willing to offer your service unto the Lord?"