11 Therefore David took hold of his own clothes and tore them, and so did all the men who were with him. 12 And they mourned and wept and fasted until evening for Saul and for Jonathan his son, for the people of the Lord and for the house of Israel, because they had fallen by the sword. 13 Then David said to the young man who told him, "Where are you from?" And he answered, "I am the son of an alien, an Amalekite." 14 So David said to him, "How was it you were not afraid to put forth your hand to destroy the Lord's anointed?" 15 Then David called one of the young men and said, "Go near, and execute him!" And he struck him so that he died. 16 So David said to him, "Your blood is on your own head, for your own mouth has testified against you, saying, 'I have killed the Lord's anointed.' "
Matthew Henry's Commentary on 2 Samuel 1:11-16
Commentary on 2 Samuel 1:11-16
(Read 2 Samuel 1:11-16)
David was sincere in his mourning for Saul; and all with him humbled themselves under the hand of God, laid so heavily upon Israel by this defeat. The man who brought the tidings, David put to death, as a murderer of his prince. David herein did not do unjustly; the Amalekite confessed the crime. If he did as he said, he deserved to die for treason; and his lying to David, if indeed it were a lie, proved, as sooner or later that sin will prove, lying against himself. Hereby David showed himself zealous for public justice, without regard to his own private interest.