To reject the promise that sins are freely forgiven for Christ's sake is to abolish the Gospel...

In order for the subject to be made quite clear, we have shown well enough so far, both from testimonies of Scripture and arguments derived from Scripture, that we receive forgiveness of sins for Christ's sake through faith alone.  We have shown that through faith alone we are justified, that is, unrighteous people are made righteous, or regenerated.  How necessary the knowledge of this faith is can be easily judged.  Because Christ's office is recognized in this alone, we receive Christ's benefits by this alone.  Only this teaching brings sure and firm consolation to pious minds.  In the Church there must be teaching by which the pious may receive the sure hope of salvation.  For the adversaries give people bad advice when they tell them to doubt whether they receive forgiveness of sins.  How will such persons sustain themselves in death who have heard nothing of this faith and think that they ought to doubt whether they receive forgiveness of sins?  Besides, it is necessary that the Gospel be kept in Christ's Church, namely, the promise that sins are freely forgiven for Christ's sake.  Those who teach nothing of this faith we speak about, completely abolish the Gospel.  But the Scholastics mention not even a word about this faith. Our adversaries follow them and reject this faith.  Nor do they see that by rejecting this faith they abolish the entire promise about the free forgiveness of sins and the righteousness of Christ.
~BOC, AP, IV (II), 117-121.