1 Samuel 27:9

And he seized Agag the king of the Amalekites alive and devoted to destruction all the people with the edge of the sword.

Then Achish called David and said to him, “As Yahweh lives, you have been upright, and your going out and your coming in with me in the camp are pleasing in my sight; for I have not found evil in you from the day of your coming to me to this day. Nevertheless, you are not pleasing in the sight of the lords.

Then it happened when David and his men came to Ziklag on the third day, that the Amalekites had made a raid on the Negev and on Ziklag and had struck Ziklag and burned it with fire;