of gold for the [things of] gold, and of silver for the [things of] silver, and for all manner of work [to be made] by the hands of artificers. Who then offers willingly to consecrate himself this day to Yahweh?
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?"