1 Samuel 15:10-23 NIV
Then the word of the LORD came to Samuel: “I regret that I have made Saul king, because he has turned away from me and has not carried out my instructions.” Samuel was angry, and he cried out to the LORD all that night.
Early in the morning Samuel got up and went to meet Saul, but he was told, “Saul has gone to Carmel. There he has set up a monument in his own honor and has turned and gone on down to Gilgal.”
When Samuel reached him, Saul said, “The LORD bless you! I have carried out the LORD’s instructions.”
But Samuel said, “What then is this bleating of sheep in my ears? What is this lowing of cattle that I hear?”
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.”
“Enough!” Samuel said to Saul. “Let me tell you what the LORD said to me last night.”
“Tell me,” Saul replied.
Samuel said, “Although you were once small in your own eyes, did you not become the head of the tribes of Israel? The LORD anointed you king over Israel. And he sent you on a mission, saying, ‘Go and completely destroy those wicked people, the Amalekites; wage war against them until you have wiped them out.’ Why did you not obey the LORD? Why did you pounce on the plunder and do evil in the eyes of the LORD?”
“But I did obey the LORD,” Saul said. “I went on the mission the LORD assigned me. I completely destroyed the Amalekites and brought back Agag their king. The soldiers took sheep and cattle from the plunder, the best of what was devoted to God, in order to sacrifice them to the LORD your God at Gilgal.”
But Samuel replied:
“Does the LORD delight in burnt offerings and sacrifices
as much as in obeying the LORD?
To obey is better than sacrifice,
and to heed is better than the fat of rams.
For rebellion is like the sin of divination,
and arrogance like the evil of idolatry.
Because you have rejected the word of the LORD,
he has rejected you as king.”
NIV: New International Version