Charles H. Spurgeon on Psalms 37:15

Their sword shall enter into their own heart. Like Haman they shall be hanged upon the gallows built by themselves for Mordecai. Hundreds of times has this been the case. Saul, who sought to slay David, fell on his own sword; and the bow, his favourite weapon, the use of which he taught the children of Israel, was not able to deliver him on Gilboa. And their bows shall be broken. Their inventions of evil shall be rendered useless. Malice outwits itself. It drinks the poisoned cup which it mixed for another, and burns itself in the fire which it kindled for its neighbour. Why need we fret at the prosperity of the wicked when they are so industriously ruining themselves while they fancy they are injuring the saints? The next nine verses mainly describe the character and blessedness of the godly, and the light is brought out with a few black touches descriptive of the wicked and their doom.