"I Delight to do Your Will" Psalm 40

David in this Psalm declares the Lord to be his help and deliverer.  He understood that God wasn't interested in sacrifices but hearts to obey.  He tells of the Law of God written on his heart.  It is this that gives him the desire to do that which delights the Lord.  His attention is on his enemies but quickly he turns back to the Lord as his deliverer.