Distinguishing Gospel from Law
Martin Luther
Those who know how to tell the difference between the law and the gospel should thank God and consider themselves true theologians. In times of temptation, I certainly don’t know how to do this as I should. You can keep these two separate by placing the gospel in heaven and the law on earth. Call the righteousness of the gospel heavenly and divine, and call the righteousness of the law earthly and human.
You should distinguish the righteousness of the gospel from the righteousness of the law as carefully as God has separated heaven from earth, light from darkness, and day from night. You should consider one as light and day, the other as darkness and night. If only you could separate them even further.
So when dealing with matters of faith and conscience, you should exclude the law and let it remain on earth. But when dealing with how we are to live in this world, you should light the lamp of the law. So the immeasurable light of the gospel will illuminate the day, and the lamp of the law will illuminate the night.
If you have a conscience terrified by a sense of sin, you should think to yourself, “While I am on earth, I must work. Just as a donkey should work, serve, and carry the burdens given to it, so my body should obey the law. But when I ascend to heaven, I leave the donkey with its burden on earth.
My conscience doesn’t have anything to do with the law, works, or earthly righteousness.” So the donkey remains in the valley, while the conscience climbs with Isaac up the mountain. It knows absolutely nothing of the law and its works. Instead, the conscience only keeps its eye on the forgiveness of sins and Christ’s righteousness.
Source: Quoted in Faith Alone: A Daily Devotional, p. 122. James C. Galvin. Zondervan (2009).