Romans 3:5 - Matthew Poole's English Annotations on the Holy Bible

But if our unrighteousness commend the righteousness of God; an anticipation of another objection, which might be lnade upon the preceding words: that if the faithfulness of God, in keeping his promises, doth appear in and notwithstanding the unfaithfulness of men, then we gather thus much, that the fidelity of God is rendered a great deal more commendable by the perfidiousness of man. What shall we say? Thus we object, or this will be the inconvenience. Is God unrighteous who taketh vengeance? i.e. then God is unjust in punishing the Jews, or any other wicked men, for that which tends to his own glory, and the commendations of his veracity. I speak as a man; this is the language of carnal men, and such blasphemy they speak; I recite the objection of some men, and speak after their carnal manner.