12 And they mourned and wept and fasted until evening for Saul and for Jonathan his son and for the people of the Lord and for the house of Israel, because they had fallen by the sword.
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.
Matthew Henry's Commentary on 2 Samuel 1:12
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.