Samuel said to Jesse, Are here all your children? He said, There remains yet the youngest, and, behold, he is keeping the sheep. Samuel said to Jesse, Send and get him; for we will not sit down until he come here.
Actually, David had a great admiration for Saul. Of course just a young boy, and he was at that hero age, and Saul, big, tall, handsome fellow became sort of a hero in David's eyes. David always respected Saul right to his death and even after his death. David never lost his respect for this man.