David is not a king that worships, but rather, a worshiper who is a king.  David has a heart of worship. “A heart of worship is released out of an understanding of a CAUSE and a REVELATION.”  What he knew, we need to know: there is a cause and a revelation in Israel.

“Let us bring the ark of our God back to us, for we have not inquired at it since the days of Saul.” Then all the assembly said that they would do so, for the thing was right in the eyes of all the people.” 1 Chronicles 13:3-4