Dietrich Bonhoeffer on cheap grace and costly grace

It seems that everyone is talking about Dietrich Bonhoeffer at the moment. Here are a few famous Bonhoeffer quotes I've found on the Internet.

On cheap grace

"Cheap grace means grace as a doctrine, a principle, a system. It means forgiveness of sins proclaimed as a general truth, the love of God taught as the Christian 'conception' of God. An intellectual assent to that idea is held to be of itself sufficient to secure remission of sins. The Church which holds the correct doctrine of grace has, it is supposed, ipso facto a part in that grace. In such a Church the world finds a cheap covering for its sins; no contrition is required, still less any real desire to be delivered from sin. Cheap grace therefore amounts to a denial of the living Word of God, in fact, a denial of the Incarnation of the Word of God." (emphasis added)

"Cheap grace means the justification of sin without the justification of the sinner. Grace alone does everything, they say, and so everything can remain as it was before."

"Cheap grace is grace without discipleship, grace without the cross, grace without Jesus Christ, living and incarnate."

On costly grace

"Costly grace is the treasure hidden in the field; for the sake of it a man will gladly go and sell all that he has... It is the kingly rule of Christ,..., it is the call of Jesus Christ at which the disciple leaves his nets and follows him."

"Such grace is costly because it calls us to follow, and it is grace because it calls us to follow Jesus Christ. It is costly because it costs a man his life, and it is grace because it gives a man the only true life. It is costly because it condemns sin, and grace because it justifies the sinner. Above all, it is costly because it cost God the life of his Son: 'ye were bought at a price,' and what has cost God much cannot be cheap for us. Above all, it is grace because God did not reckon his Son too dear a price to pay for our life, but delivered him up for us. Costly grace is the Incarnation of God."

"Costly grace confronts us as a gracious call to follow Jesus, it comes as a world of forgiveness to the broken spirit and the contrite heart. Grace is costly because it compels a man to submit to the yoke of Christ and follow him; it is grace because Jesus says: 'My yoke is easy and my burden is light.'"