Then the princes of the Philistines went forth: and it happened, as often as they went forth, that David behaved himself more wisely than all the servants of Saul; so that his name was much set by.
He set up a dowry regarding the Philistines. David went out and gave him double dowry. So Saul then of course was sort of shocked and surprised. He figured David would get wiped out in going out against the Philistines.