1 Samuel 15:17-19

17And Samuel told him, “Although you may think little of yourself, are you not the leader of the tribes of Israel? The Lord has anointed you king of Israel.

18And the Lord sent you on a mission and told you, ‘Go and completely destroy the sinners, the Amalekites, until they are all dead.’

19Why haven’t you obeyed the Lord? Why did you rush for the plunder and do what was evil in the Lord’s sight?”