1 Samuel 15:18-20

And the LORD sent you on a mission and said, ‘Go, devote to destruction 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 pounce on the spoil and do what was evil in the sight of the LORD?” And Saul said to Samuel, “I have obeyed the voice of the LORD. I have gone on the mission on which the LORD sent me. I have brought Agag the king of Amalek, and I have devoted the Amalekites to destruction.