“[Faith] alone, and nothing else, is the means or instrument with and through which God’s grace and Christ’s merit in the Gospel promise are received, apprehended, applied to us, and appropriated. Love and all other virtues or works are excluded from this office and property of such application or appropriation.”
“Neither renewal, sanctification, virtues, nor good works are at all a form, part, or cause of justification, that is, our righteousness before God. They are not to stand or be set up as a part or cause of our righteousness. They are not to be mixed into the article of justification under any pretext, title, or name whatever, as though they are necessary and belong to justification. The righteousness of faith stands alone in the forgiveness of sins out of pure grace, for the sake of Christ’s merit alone. These blessings are brought to use in the Gospel and are received, accepted, applied, and appropriated through faith alone.”
“Faith makes righteous only because, as a means and instrument, it lays hold of, and accepts, God’s grace and Christ’s merit in the Gospel promise.”
Solid Declaration of the Formula of Concord, III.37 & 43.