151 And Samuel said unto Saul, Jehovah sent me to anoint thee to be king over his people, over Israel: now therefore hearken thou unto the voice of the words of Jehovah. 2 Thus saith Jehovah of hosts, I have marked that which Amalek did to Israel, how he set himself against him in the way, when he came up out of Egypt. 3 Now go and smite Amalek, and utterly destroy all that they have, and spare them not; but slay both man and woman, infant and suckling, ox and sheep, camel and ass. 4 And Saul summoned the people, and numbered them in Telaim, two hundred thousand footmen, and ten thousand men of Judah. 5 And Saul came to the city of Amalek, and laid wait in the valley. 6 And Saul said unto the Kenites, Go, depart, get you down from among the Amalekites, lest I destroy you with them; for ye showed kindness to all the children of Israel, when they came up out of Egypt. So the Kenites departed from among the Amalekites.
Matthew Henry's Commentary on 1 Samuel 15:1-6
Commentary on 1 Samuel 15:1-9
(Read 1 Samuel 15:1-9)
The sentence of condemnation against the Amalekites had gone forth long before, Revelation 18:4. As the commandment had been express, and a test of Saul's obedience, his conduct evidently was the effect of a proud, rebellious spirit. He destroyed only the refuse, that was good for little. That which was now destroyed was sacrificed to the justice of God.