After God delivers the enemies of David to him on a silver platter, after all the boards are secure.  Prosperity overflows to David from the hand of God.  David finds himself in the cool of the day when "The kings rose to go to war".  David had taken the time to be idol, and rest.  This was just the chance for his heart to wonder from the Faithful God who had blessed him so.  Grab your bible and lets study together!