3 Now go and strike Amalek and devote to destruction[1] all that they have. Do not spare them, but kill both man and woman, child and infant, ox and sheep, camel and donkey.'" 4 So Saul summoned the people and numbered them in Telaim, two hundred thousand men on foot, and ten thousand men of Judah. 5 And Saul came to the city of Amalek and lay in wait in the valley. 6 Then Saul said to the Kenites, "Go, depart; go down from among the Amalekites, lest I destroy you with them. For you showed kindness to all the people of Israel when they came up out of Egypt." So the Kenites departed from among the Amalekites. 7 And Saul defeated the Amalekites from Havilah as far as Shur, which is east of Egypt. 8 And he took Agag the king of the Amalekites alive and devoted to destruction all the people with the edge of the sword. 9 But Saul and the people spared Agag and the best of the sheep and of the oxen and of the fattened calves[2] and the lambs, and all that was good, and would not utterly destroy them. All that was despised and worthless they devoted to destruction.
Matthew Henry's Commentary on 1 Samuel 15:3-9
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.