From the Confessions: The Defense of the Augsburg Confession
Concerning Love and the Fulfilling of the Law
Third, how will the conscience know when a work has been done through this inclination of love so that it is assured it has merited grace de condigno? This distinction, that people merit at one time de congruo and at another time de condigno, was devised to elude the Scriptures. As we have already said, the intention of the one who works does not distinguish the kinds of merit. In their security, hypocrites simply think their works are worthy, and that for this reason they are accounted righteous. Yet, terrified consciences doubt concerning all works, and for this reason are continually seeking other works. For this is what it means to merit de congruo: to doubt and to work without faith until despair takes place. In a word, all that the adversaries teach in regard to this matter is full of errors and dangers.
Pulling It Together: Some people have faith in their works. They believe that there are certain things they can do to earn God’s grace. This imagined acquisition of grace is called condignity or de condigno. It betrays a lack of faith in the finished work of Christ, trusting instead, that God will dignify human works with the grace of forgiveness and righteousness. There are others, sometimes those same people, who doubt the merit of condignity (as they should) and grasp at any good work in the hope that God will offer his grace in return. This is the so-called merit of congruity or de congruo, in which people hope that their efforts will bring them into harmony with God.
How can either condignity or congruity offer hope to the despairing soul? They cannot. Only Christ offers hope that is so sure and steadfast that it is an anchor for the soul. If our anchor is in self, the winds of doubt will drag us across the ocean to shipwreck. But when our hope is in Christ, the anchor holds.
Prayer: Give me faith to trust in you, Lord, my Rock and the anchor of my soul. Amen.
The Smalcald Articles are often considered Luther's theological Last Will and Testament. Written in easy-to-understand language, this study is presented in a discussion formation with assigned readings from the Scriptures and the Book of Concord. Included in the study is a shorter work by Philip Melanchton called "The Treatise on the Power and Primacy of the Pope."