Luther, Romans and the Augsburg Article

Luther's own account placed the turn in his reading of Romans 1:17, where the righteousness of God ceased to be the standard by which he would be judged and became the righteousness God gives. From that reading followed a distinction he treated as the hinge of everything: the law shows a person what is owed and cannot supply it, while the gospel announces what has been supplied. Justification is therefore not a process a believer completes but a verdict already pronounced, received by the empty hand of faith.

Melanchthon gave the position its confessional form in 1530. Article IV of the Augsburg Confession is four sentences long and states that people cannot be justified before God by their own powers, merits or works, but are justified freely for Christ's sake through faith, when they believe that they are received into favour and that their sins are forgiven on his account. The vocabulary is deliberately forensic, drawn from the law courts rather than from medicine: righteousness is imputed, reckoned to the believer's account, not infused into them as a quality that grows.

The Reformers were careful about the objection they knew was coming, that a verdict without change licenses whatever the believer pleases. Their answer was that faith is never alone even though it justifies alone, since the faith that receives Christ receives him whole and cannot receive him without being remade. Good works are the fruit that follows and the evidence that faith is real; they are simply not the ground of the verdict.