David said in his heart, I shall now perish one day by the hand of Saul: there is nothing better for me than that I should escape into the land of the Philistines; and Saul will despair of me, to seek me any more in all the borders of Israel: so shall I escape out of his hand.
So David then and his men began to invade areas around them. Now though I admire David for a lot of things, yet I don't admire David for other things. This I cannot really find any real excuse for David's actions. He would go out and he would totally wipe out a city, and he'd kill everybody so that there'd be no one to come back and tell people what was happening. He was making excursions against these cities.