1 Samuel 15:13-19 NIV

13 When Samuel reached him, Saul said, "The LORD bless you! I have carried out the LORD's instructions."
14 But Samuel said, "What then is this bleating of sheep in my ears? What is this lowing of cattle that I hear?"
15 Saul answered, "The soldiers brought them from the Amalekites; they spared the best of the sheep and cattle to sacrifice to the LORD your God, but we totally destroyed the rest."
16 "Stop!" Samuel said to Saul. "Let me tell you what the LORD said to me last night." "Tell me," Saul replied.
17 Samuel said, "Although you were once small1 in your own eyes, did you not become the head of the tribes of Israel? The LORD anointed you king over Israel.

References for 1 Samuel 15:17

18 And he sent you on a mission, saying, 'Go and completely destroy those wicked people, the Amalekites; make war on them until you have wiped them out.'
19 Why did you not obey the LORD? Why did you pounce on the plunder2 and do evil in the eyes of the LORD?"

References for 1 Samuel 15:19