Costly Grace Crucifies Cheap Grace

What follows is an excerpt from Bonhoeffer's The Cost of Discipleship.  I think it sums up what he's on about in the book.  He provides a healthy corrective for our sinful tendency to abuse and mutilate grace beyond recognition.  In this part of chapter 1, he is speaking about those who abuse and distort the grace of God and justification by faith alone and turn it all into licentiousness.

The Christian life comes to mean nothing more than living in the world and as the world, in being no different from the world, in fact, in being prohibited from being different from the world for the sake of grace.  The upshot of it all is that my only duty as a Christian is to leave the world for an hour or so on a Sunday morning and go to church to be assured that my sins are all forgiven.  I need no longer try to follow Christ, for cheap grace, the bitterest foe of discipleship, which true discipleship must loathe and detest, has freed me from that.  Grace as the data for our calculations means grace at the cheapest price, but grace as the answer to the sum means costly grace.  It is terrifying to realize what use can be made of a genuine evangelical doctrine.

Terrifying indeed.  God help us from embracing and holding out cheap grace.