"On Preaching" from the Confessions (#16)
Our opponents never mentioned faith, by which we freely receive the forgiveness of sins. All their books and sermons were silent about the exercise of faith in its struggle with despair and about the free forgiveness of sins for Christ’s sake. (Tappert, The Book of Concord. Fortress Press: Philadelphia, 1959, p.257; Apology XXIV: 46)