Take note, therefore, of a new righteousness and a new definition of righteousness. For one usually says: “Righteousness is the virtue that renders to everyone his due.” Here it is stated that righteousness is faith in Jesus Christ or the virtue by which one believes in Jesus Christ, as in Rom. 10:10: “With the heart man believes unto righteousness”; that is, if anyone wants to be righteous, it is necessary for him to believe in Christ with his heart. And in the third chapter St. Jerome says: “Well put is that true statement of a wise man that the believer does not live as the result of righteousness but is righteous by faith.” A beautiful statement indeed!
It follows now that the man who is righteous through faith does not through himself give to anyone what is his; he does this through Another, namely, Jesus Christ, who alone is so righteous as to render to all what should be rendered them. As a matter of fact, they owe everything to Him. But he who believes in Christ and by the spirit of faith has become one with Him not only renders satisfaction now to all but also brings it about that they owe everything to him, since he has all things in common with Christ. His sins are no longer his; they are Christ’s. But in Christ sins are unable to overcome righteousness. In fact, they themselves are overcome. Hence they are destroyed in him. Again, Christ’s righteousness now belongs not only to Christ; it belongs to His Christian. Therefore the Christian cannot owe anything to anyone or be oppressed by his sins, since he is supported by such great righteousness.
Martin Luther, Luther’s Works, Vol. 27: Lectures on Galatians, 1535, Chapters 5-6; 1519, Chapters 1-6, ed. Jaroslav Jan Pelikan, Hilton C. Oswald, and Helmut T. Lehmann, vol. 27 (Saint Louis: Concordia Publishing House, 1999), 240–41.