Charles H. Spurgeon on Psalms 94:1

0 LORD God, to whom vengeance belongeth. It may perhaps seem to accord too little with a lover of piety, so strenuously to urge upon God to show himself an avenger against the wicked, and to rouse Him as if He were lingering and procrastinating. But this supplication must be regarded in its proper bearing; for David does not pray, neither should we pray, that God would take vengeance on the wicked in the same way that men, inflamed with anger and hatred, are wont often to avenge themselves of their enemies, but that He would punish them after his own divine manner and measure. The vengeance of God is for the most part a medicine for the evil; but ours is at times destruction even to the good. Therefore truly the Lord is alone the God of revenges. For we, when we think we have inflicted a penalty upon our enemy, are often much mistaken. What injury to us was the body of our enemy? in depriving him of which we nevertheless express all our bitterness. What wounded thee and wrought thee harm and shame, was the spirit of thine enemy, and that thou art not able to seize and hold, but God is able; and He alone has such power that in no way can the spirit escape his strength and force. Leave vengeance with Him, and He will repay. He admonishes us, that if we ourselves wish to be avengers of our own pains and injuries we may hurt ourselves more deeply than our enemy: for when we take vengeance on him, we indeed wound and do violence to his body, which in itself is vile and of little regard; but in our own best and most precious part, that is, in our spirit; we ourselves, by losing patience, receive a deep stain, because when virtue and humanity have been expelled thence, we meanwhile incur faults to be atoned for therein. Wherefore God is entreated to become Himself the avenger of our injuries, for He alone knows aright and is able to avenge; and to become such an avenger that only the very thing which injured us may be punished. Some greedy man has cheated thee in money, may He punish avarice in him. A proud man has treated thee with scorn, may He destroy his pride, etc... This is vengeance most worthy to be inflicted of God, and by us to be sought. Jacopo Sadoleto. 1477-1547.