Justification Of Sin Not From Sin

"Luther had said that grace alone can save; his followers took up his doctrine and repeated it word for word. But they left out its invariable corollary, the obligation of discipleship. There was no need for Luther always to mention that corollary explicitly for he always spoke as one who had been led by grace to the strictest following of Christ. Judged by the standard of Luther's doctrine, that of his followers was unassailable, and yet their orthodoxy spelt the end and destruction of the Reformation as the revelation on earth of the costly grace of God. The justification of the sinner in the world degenerated into the justification of sin and the world. Costly grace was turned into cheap grace without discipleship."

- Dietrich Bonhoeffer. The Cost Of Discipleship.