“The main knowledge and true wisdom of Christians, then, is this: to regard as very serious and true these words of Paul, that Christ was given over to death, not for our righteousness or holiness but for our sins, which are real sins—great, many, in fact, infinite and invincible. Therefore you must not think of them as minor or suppose that your own works can remove them. Nor must you despair on account of their gravity if you feel them oppressing you either in life or in death. But you must learn from Paul here to believe that Christ was given, not for sham or counterfeit sins, nor yet for small sins, but for great and huge sins; not for one or two sins but for all sins; not for sins that have been overcome—for neither man nor angel is able to overcome even the tiniest sin—but for invincible sins. And unless you are part of the company of those who say “our sins,” that is, who have this doctrine of faith and who teach, hear, learn, love, and believe it, there is no salvation for you.”
Martin Luther, vol. 26, Luther's Works, Vol. 26 : Lectures on Galatians, 1535, Chapters 1-4, ed. Jaroslav Jan Pelikan, Hilton C. Oswald and Helmut T. Lehmann, Luther's Works, 26:35 (Saint Louis: Concordia Publishing House, 1999, c1963).