1 Samuel 15:16-18

16Samuel said to Saul, ‘Listen to me! I will tell you what the Lord said to me last night.’ Saul said, ‘Tell me.’

17Samuel said, ‘At one time, you thought that you were not an important person. Now you have become the leader of all the tribes of Israel. The Lord chose you to be king of Israel.

18He gave you a job to do. He told you, “Go and kill all those wicked Amalekites. Fight against them until you have destroyed them all.”