Romans 3:21
21But now apart from the law, a righteousness of God has been revealed, being testified by the law and the prophets;
But now apart from the law, a righteousness of God has been revealed, witnessed by the Law and the Prophets. Wesley: the righteousness of God is the manner of becoming righteous which God hath appointed; without the law means without the previous obedience the law requires. It is manifested in the gospel, and attested by Moses and the Prophets.
Both camps must say this together first: this righteousness is God's, not ours; it stands apart from the works of the law; it is not a novelty against Scripture. Wesleyan Arminians find a gospel righteousness sincerely offered, prepared by God and now made public. "Apart from the law" is not antinomian; it is apart from previous obedience as the way of becoming righteous.
Calvin: this righteousness, which God communicates to man and accepts alone, has been revealed without the law—that is, without the aid of the law, meaning works. He blends not works with the mercy of God; having wholly removed all confidence in works, he sets up mercy alone. The Law and the Prophets bear witness, lest free righteousness seem to militate against the law.
The righteousness manifested is God's, forensic and free. The gospel does not invent it; the Old Testament already testified. Works of every kind, even those the faithful perform, are excluded from the verdict. "But now" is the open manifestation in Christ of what the types and promises already said.