Charles H. Spurgeon on Psalms 58:7

Let them melt away as waters which run continually. Like mountain torrents dried up by the summer heats let them disappear; or like running streams whose waters are swiftly gone, so let them pass away; or like water spilt which none can find again, so let them vanish out of existence. Begone, ye foul streams, the sooner ye are forgotten the better for the universe. When he bendeth his bow to shoot his arrows, let them be as cut in pieces. When the Lord goes forth to war, let his judgments so tell upon these persecutors that they may be utterly cut in pieces as a mark shattered by many shafts. Or perhaps the meaning is, when the ungodly man marches to the conflict, let his arrows and his bow drop into fragments, the string cut, the bow snapped, the arrows headless, the points blunted; so that the boastful warrior may not have wherewithal to hurt the object of his enmity. In either sense the prayer of the Psalm has often become fact, and will be again fulfilled as often as need arises.