2 Samuel 1:13-16

13David asked the young man who had brought the report to him, ‘Where are you from?’ The man replied, ‘I am an Amalekite, the son of a foreign man who lives in Israel.’

14David said to him, ‘The Lord had chosen Saul to be Israel's king. You should have been very afraid to kill him!’

15Then David said to one of his own young men, ‘Go and knock him down!’ So the man knocked him down so that he died.

16David had said to the Amalekite, ‘You deserve to die because of what you have said. Your own words show that you did a bad thing. You yourself said, “I have killed the Lord's chosen king.” ’