Saul was very angry, and this saying displeased him; and he said, They have ascribed to David ten thousands, and to me they have ascribed but thousands: and what can he have more but the kingdom?
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.