It was never that David was such a phenomenal warrior; he was a phenomenal believer who could trust God at any juncture. So the real question is whether God can trust you with the great victories that want to fall your way, whether you will believe what He said over what you see. The world will follow your faith, which is why the church's pretending has cost it so much. When you surrender your will to His, that is not works you can boast in; it is the exchange that gives you His favor, and a peace nothing can shake.