2 Samuel 1:11-16

11Then David took hold of his own clothes and tore them, and all the men who were with him did the same. 12They mourned and wept and fasted until evening for Saul and his son Jonathan, and for the people of the LORD and the house of Israel, because they had fallen by the sword.

13And David inquired of the young man who had brought him the report, “Where are you from?”

“I am the son of a foreigner,” he answered. “I am an Amalekite.”

14So David asked him, “Why were you not afraid to lift your hand to destroy the LORD’s anointed?” 15Then David summoned one of the young men and said, “Go, execute him!” So the young man struck him down, and he died. 16For David had said to the Amalekite, “Your blood be on your own head because your own mouth has testified against you, saying, ‘I killed the LORD’s anointed.’”