This thing isn't good that you have done. As Yahweh lives, you are worthy to die, because you have not kept watch over your lord, Yahweh's anointed. Now see where the king's spear is, and the jar of water that was at his head.
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."