"Cheap grace means justification of sin without the justification of the sinner. Grace alone does everything they say, and so everything can remain as it was before. … Well, then, let the Christian live like the rest of the world, let him model himself on the world’s standards in every sphere of life, and not presumptuously aspire to live a different life under grace from his old life under sin. That was the heresy of the enthusiasts, the Anabaptists and their kind. … Let him live like the rest of the world! Of course he would like to go and do something extraordinary, and it does demand a good deal of self-restraint to refrain from the attempt and content himself with living as the world lives. Yet it is imperative for the Christian to achieve renunciation, to practice self-effacement."
January 1, 1970
https://en.wikiquote.org/wiki/Dietrich_Bonhoeffer