Dietrich Bonhoeffer begins The Cost of Discipleship with a rant.
Cheap grace is the deadly enemy of our Church. We are fighting to-day for costly grace.
Cheap grace means grace sold on the market like cheapjacks’ wares. The sacraments, the forgiveness of sin, and the consolations of religion are thrown away at cut prices. Grace is represented as the Church’s inexhaustible treasury, from which she showers blessings with generous hands, without asking questions or fixing limits. Grace without price; grace without cost! The essence of grace, we suppose is that the account has been paid in advance; and, because it has been paid, everything can be had for nothing. Since the cost was infinite, the possibilities of using and spending it are infinite. What would grace be if it were not cheap?
In case you find the first paragraph to be ambiguous ;), I will finish this post with the opening sentences of the many of the remaining paragraphs in the chapter. In his succinct style they function like outline bullet points:
Cheap grace means grace as a doctrine, a principle, a system … an intellectual assent.
Cheap grace means the justification of sin without the justification of the sinner.
Cheap grace is the preaching of forgiveness without requiring repentance, baptism without church discipline, Communion without confession, absolution without personal confession. Cheap grace is grace without discipleship, grace without the cross, grace without Jesus Christ, living and incarnate.
Cheap grace is the grace we bestow on ourselves.
Costly grace is the gospel which must be sought again and again, the gift which must be asked for, the door at which a man must knock. [ital. in original.]