Then said Saul, I have sinned: return, my son David; for I will no more do you harm, because my life was precious in your eyes this day: behold, I have played the fool, and have erred exceedingly.
Saul underneath knew that someday David was gonna take the throne. He was trying to protect the throne and to pass it onto his own children. But yet in his heart, he knew that God had anointed David, and that David was God's anointed king. "Then Saul said to David, Blessed be thou, my son David: thou shalt both do great things, and still prevail."