I Samuel 15:18-20

Now the Lord sent you on a mission, and said, ‘Go, and utterly destroy the sinners, the Amalekites, and fight against them until they are consumed.’ Why then did you not obey the voice of the Lord? Why did you swoop down on the spoil, and do evil in the sight of the Lord?” And Saul said to Samuel, “But I have obeyed the voice of the Lord, and gone on the mission on which the Lord sent me, and brought back Agag king of Amalek; I have utterly destroyed the Amalekites.