Only the gospel justifies.
The good news of the crucified Christ actually brings about what our souls long for the most.

I’ve been on a tear of late, amassing a bookshelf worth of some of Martin Luther’s works along with several other entries from his constituents or disciples examining the longevity and biblical precision of his writings. If I didn’t know better, I’d be worried I was accumulating resources for another book! And although I’m not ruling that out, it’s the worst-kept secret that the Christian book market is saturated, for better or worse, with inquiries into Luther’s life and legacy. There is a good reason for that, though, at least in my estimation, since the majority of Luther’s works resonate with the deepest problem of the human heart — namely, how one is justified before God.
I don’t think it’s too reductive to say that the prevailing theme of Luther’s works is the articulation of the gospel of justification by faith in the death and resurrection of Christ alone. This isn’t to say that Luther was a one-note theologian, but it is to say that this conviction permeates everything else. And that’s just how it should be, I do believe. Everyone who’s ever lived has been on a quest for justification. Many wouldn’t put it in those terms, perhaps, but at the level of the human soul, that’s all we’re after. We are all pining for the day when we are told we are enough, when we are told we are accepted, and when we can finally stand in the light, unafraid and unashamed. Our endeavors at finding this or manufacturing this for ourselves always come up short. What’s more, they often cause more problems than they resolve. It is only the free gift of justification, as dispensed in the good news of the crucified Christ, that actually brings about what our souls long for the most. That is to say, only the gospel justifies.
In William Herman Theodore Dau’s 1917 re-evaluation of Luther himself, Luther Examined and Reexamined, we find the following passage, which gets to the heart of what I’m talking about. Dau writes:
Luther held that justifying faith is essentially the assurance that since Christ lived on earth as a man, labored, suffered, died, and rose again in the place of sinners, the world en masse and every individual sinner are without guilt in the estimation of God. “God was in Christ, reconciling the world unto Himself, not imputing their trespasses unto them” (2 Cor. 5:19). To this reconciliation the sinner has contributed nothing. It has been accomplished without him. He cannot add anything to it. God only asks the sinner to believe in his salvation as finished by Jesus Christ. To believe this fact does not mean to perform a work of merit in consideration of which God is willing to bestow salvation on the believer, but it means to accept the work of Christ as performed in our place, to rejoice therein, and to repose a sure confidence in this salvation in defiance of the accusations of our own conscience, the incriminations which the broken Law of God hurls at us, and the terrors of the final judgment. The believer regards himself as righteous before God not because of any good work that he has done, but because of the work which Christ has performed in his place. The believer holds that, when God, by raising Christ from the dead, accepted His work as a sufficient atonement for men’s guilt and an adequate fulfillment of the divine Law, He accepted each and every sinner. The believer is certain that through the work of his Great Brother, Christ, he has been restored to a child relationship with God and enjoys child’s privileges with his Father in heaven. The idea that he himself has done anything to bring about this blessed state of affairs is utterly foreign to this faith in Christ. (93–94)
The hardest news to accept is likewise the best news of all — namely, that we can do nothing to accomplish our justification, nor can we make it more “sure.” Instead, the good news is that our justification is sure, complete, and settled for us already in the life, death, and resurrection of Another. Jesus Christ has fulfilled everything necessary to absolve you of every single sin. And what sweetens this good news is just the fact that you and I are declared free from sin, guilt, and shame apart from anything we’ve done. You and I aren’t enough, aren’t accepted in and of ourselves. But, praise be, we’ve been gifted the enough-ness of Christ, “wherein he hath made us accepted in the beloved” (Eph. 1:6 KJV). No subsequent works are required; no extra addendums have been added. You are free, my friend. Your justification is sure because of Christ alone. Rest and rejoice in him today.
Grace and peace to you.
Works cited:
W. H. T. Dau, Luther Examined and Reexamined: A Review of Catholic Criticism and a Plea for Revaluation (St. Louis: Concordia, 1917).
Thanks for that Brad. The message is that God isn't intending to have a war with us. We keep attacking Him and He just waits for us to run out of ammunition so that we can be together again.
As you say our justification is complete, and we can rest from our own works. But then, what happens after that? We remain alive in the world, and the Bible says a great deal about how we are supposed to live in the world after our justification - not rules to earn salvation, but out of obedience and love to Christ and as fruits of the Spirit that has been given to us. Since this is contrary to our old man, to the flesh, we have to die to self to live lives of righteousness, not our own righteousness, but the righteousness of Christ, which is supposed to now have something to do with the way we think, act and live.
Luther wrote a great deal about this also. Not how to be justified, but about how, with God's help, we are supposed to live after justification. Here is a passage from Luther's PREFACE TO ROMANS:
"Faith is a work of God in us, which changes us and brings us to birth anew from God (cf. John 1). It kills the old Adam, makes us completely different people in heart, mind, senses, and all our powers, and brings the Holy Spirit with it. What a living, creative, active powerful thing is faith! It is impossible that faith ever stop doing good. Faith doesn't ask whether good works are to be done, but, before it is asked, it has done them. It is always active. WHOEVER DOESN'T DO SUCH WORKS IS WITHOUT FAITH; he gropes and searches about him for faith and good works but doesn't know what faith or good works are. Even so, he chatters on with a great many words about faith and good works."