151 Samuel also said to Saul, "The Lord sent me to anoint you king over His people, over Israel. Now therefore, heed the voice of the words of the Lord. 2 Thus says the Lord of hosts: 'I will punish Amalek for what he did to Israel, how he ambushed him on the way when he came up from Egypt. 3 Now go and attack Amalek, and utterly destroy all that they have, and do not spare them. But kill both man and woman, infant and nursing child, ox and sheep, camel and donkey.' " 4 So Saul gathered the people together and numbered them in Telaim, two hundred thousand foot soldiers and ten thousand men of Judah. 5 And Saul came to a city of Amalek, and lay in wait in the valley. 6 Then Saul said to the Kenites, "Go, depart, get down from among the Amalekites, lest I destroy you with them. For you 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.