One day Samuel said to Saul, "I anointed you king of Israel because the LORD told me to. Now listen to this message from the LORD!
This is what the LORD Almighty says: 'I have decided to settle accounts with the nation of Amalek for opposing Israel when they came from Egypt.
Now go and completely destroy the entire Amalekite nation -- men, women, children, babies, cattle, sheep, camels, and donkeys.'"
References for 1 Samuel 15:3
So Saul mobilized his army at Telaim. There were 200,000 troops in addition to 10,000 men from Judah.
Then Saul went to the city of Amalek and lay in wait in the valley.
Saul sent this message to the Kenites: "Move away from where the Amalekites live or else you will die with them. For you were kind to the people of Israel when they came up from Egypt." So the Kenites packed up and left.
Then Saul slaughtered the Amalekites from Havilah all the way to Shur, east of Egypt.
He captured Agag, the Amalekite king, but completely destroyed everyone else.
Saul and his men spared Agag's life and kept the best of the sheep and cattle, the fat calves and lambs -- everything, in fact, that appealed to them. They destroyed only what was worthless or of poor quality.
Then the LORD said to Samuel,
"I am sorry that I ever made Saul king, for he has not been loyal to me and has again refused to obey me." Samuel was so deeply moved when he heard this that he cried out to the LORD all night.
Early the next morning Samuel went to find Saul. Someone told him, "Saul went to Carmel to set up a monument to himself; then he went on to Gilgal."
When Samuel finally found him, Saul greeted him cheerfully. "May the LORD bless you," he said. "I have carried out the LORD's command!"
"Then what is all the bleating of sheep and lowing of cattle I hear?" Samuel demanded.
"It's true that the army spared the best of the sheep and cattle," Saul admitted. "But they are going to sacrifice them to the LORD your God. We have destroyed everything else."
Then Samuel said to Saul, "Stop! Listen to what the LORD told me last night!" "What was it?" Saul asked.
And 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.
And the LORD sent you on a mission and told you, 'Go and completely destroy the sinners, the Amalekites, until they are all dead.'
Why haven't you obeyed the LORD? Why did you rush for the plunder and do exactly what the LORD said not to do?"
"But I did obey the LORD," Saul insisted. "I carried out the mission he gave me. I brought back King Agag, but I destroyed everyone else.
Then my troops brought in the best of the sheep and cattle and plunder to sacrifice to the LORD your God in Gilgal."
But Samuel replied, "What is more pleasing to the LORD: your burnt offerings and sacrifices or your obedience to his voice? Obedience is far better than sacrifice. Listening to him is much better than offering the fat of rams.
Rebellion is as bad as the sin of witchcraft, and stubbornness is as bad as worshiping idols. So because you have rejected the word of the LORD, he has rejected you from being king."
Then Saul finally admitted, "Yes, I have sinned. I have disobeyed your instructions and the LORD's command, for I was afraid of the people and did what they demanded.
Oh, please, forgive my sin now and go with me to worship the LORD."
But Samuel replied, "I will not return with you! Since you have rejected the LORD's command, he has rejected you from being the king of Israel."
As Samuel turned to go, Saul grabbed at him to try to hold him back and tore his robe.
And Samuel said to him, "See? The LORD has torn the kingdom of Israel from you today and has given it to someone else -- one who is better than you.
And he who is the Glory of Israel will not lie, nor will he change his mind, for he is not human that he should change his mind!"
Then Saul pleaded again, "I know I have sinned. But please, at least honor me before the leaders and before my people by going with me to worship the LORD your God."
So Samuel finally agreed and went with him, and Saul worshiped the LORD.
Then Samuel said, "Bring King Agag to me." Agag arrived full of smiles, for he thought, "Surely the worst is over, and I have been spared!"
References for 1 Samuel 15:32
But Samuel said, "As your sword has killed the sons of many mothers, now your mother will be childless." And Samuel cut Agag to pieces before the LORD at Gilgal.
Then Samuel went home to Ramah, and Saul returned to his house at Gibeah.
Samuel never went to meet with Saul again, but he mourned constantly for him. And the LORD was sorry he had ever made Saul king of Israel.