The promise ought always to be in sight that God, because of His promise, wishes for Christ’s sake, and not because of the Law or our works, to be gracious and to justify. In this promise timid consciences ought to seek reconciliation and justification; by this promise they ought to sustain themselves and be confident that for Christ’s sake, because of His promise, they have a gracious God. Thus works can never render a conscience pacified, but only the promise can. If, therefore, justification and peace of conscience must be sought elsewhere than in love and works, love and works do not justify, although they are virtues and pertain to the righteousness of the Law, in so far as they are a fulfilling of the Law. So far also this obedience of the Law justifies by the righteousness of the Law. But this imperfect righteousness of the Law is not accepted by God, unless on account of faith. Accordingly it does not justify, i.e., it neither reconciles, nor regenerates, nor by itself renders us accepted before God.
From this it is evident that we are justified before God by faith alone [i.e., it obtains the remission of sins and grace for Christ’s sake, and regenerates us. Likewise, it is quite clear that by faith alone the Holy Ghost is received, again, that our works and this inchoate fulfilling of the Law do not by themselves please God. Now, even if I abound in good works like Paul or Peter, I must seek my righteousness elsewhere, namely, in the promise of the grace of Christ; again, if only faith calms the conscience, it must, indeed, be certain that only faith justifies before God. For, if we wish to teach correctly, we must adhere to this, that we are accepted with God, not on account of the Law, not on account of works, but for Christ’s sake. For the honor, due Christ, must not be given to the Law or our miserable works.] because by faith alone we receive remission of sins and reconciliation, because reconciliation or justification is a matter promised for Christ’s sake, and not for the sake of the Law. Therefore it is received by faith alone, although, when the Holy Ghost is given, the fulfilling of the Law follows.
– Apology to the Augsburg Confession, Article Four, paragraphs 180-182