From the Word
5 Not that we are competent of ourselves to claim anything as coming from us; our competence is from God, 6 who has made us competent to be ministers of a new covenant, not in a written code but in the Spirit; for the written code kills, but the Spirit gives life. 7 Now if the dispensation of death, carved in letters on stone, came with such splendor that the Israelites could not look at Moses’ face because of its brightness, fading as this was, 8 will not the dispensation of the Spirit be attended with greater splendor? 9 For if there was splendor in the dispensation of condemnation, the dispensation of righteousness must far exceed it in splendor. 10 Indeed, in this case, what once had splendor has come to have no splendor at all, because of the splendor that surpasses it. 11 For if what faded away came with splendor, what is permanent must have much more splendor.
2 Corinthians 3:5–11, RSV
The “letter” is the whole law of Moses, or the doctrine of the ten commandments, which teach how we should obey God, honor parents, love our neighbors, and the like—the very best doctrine to be found in all books, sermons and schools. There is another message, which Paul terms the “ministration of a new covenant or of the Spirit.” This doctrine does not teach what works are required of man; but it makes known to him what God would do for him and bestow upon him, indeed what he has already done; he has given his Son Christ for us; because, for our disobedience to the law, which no man fulfils, we were under God’s wrath and condemnation. Christ made satisfaction for our sins, effected a reconciliation with God and gave to us his own righteousness. This doctrine is revealed through the Holy Spirit. The Holy Spirit works in the hearts of them who hear and accept the doctrine. Therefore this ministration is termed the ministration “of the Spirit.”
It is of design that the apostle does not term the two dispensations “law” and “gospel,” but names them according to the respective effects produced. For it is impossible to keep the law without Christ, though man may, for the sake of honor or property, or from fear of punishment, feign outward holiness. The heart which does not discern God’s grace in Christ cannot turn to God, nor trust in him; it cannot love his commandments and delight in them, but rather resists them. Therefore, God would have his gospel message unceasingly urged as the means of awakening man’s heart to discern his state and recall the grace and lovingkindness of God, with the result that the power of the Holy Spirit is increased constantly. No influence of the law, no work of man is present here. The force is a new and heavenly one — the power of the Holy Spirit. He impresses upon the heart Christ and his works, making it a true book which does not consist in tracing mere letters and words, but in true life and action.
Luther, Martin, and John Sander. Devotional Readings from Luther’s Works for Every Day of the Year. Augustana Book Concern, 1915, pp. 308–09.