2 Samuel 1:12

They mourned, and wept, and fasted. The sight of Saul's royal insignia was clear proof of Israel's disaster; and this sorrow of David and his men shows how true their hearts were to their country, and how unbearable would have been their position had not the prudence of the Philistine lords extricated them from the difficulty in which they had been placed by David's want of faith. But David had other reasons besides patriotism for sorrow. Personally he had lost the truest of friends, and even Saul had a place in his heart for he would contrast with his terrible death the early glories of his reign, when all Israel honoured him as its deliverer from the crushing yoke of foreign bondage, and when David was himself one of the most trusty of his captains. Otto von Gerlach compares David thus weeping over the fall of his implacable enemy with David's Son weeping over Jerusalem, the city whose inhabitants were his bitter foes, and who not only sought his death, but delivered him up to the Romans, to be scourged and spitefully intreated, and slain upon the cross.