He went on to outline what we meant writing,
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?Later Bonhoeffer goes on to show the distinction between cheap grace, which he sees as an empty promise and costly grace, which he sees as Christ’s true teaching.
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.
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.Not one to mince words, Bonhoeffer wrote further in the same book, “Those who try to use grace as a dispensation from following Christ are simply deceiving themselves.” Eight years after writing these words, Bonhoeffer was killed in the waning days of Germany's so-called Third Reich. The pacifist ethicist was put to death for his part in a plot to assasinate Adolf Hitler.
Costly grace is the treasure hidden in the field; for the sake of it a man will gladly go and sell all the he has….it is the call of Jesus Christ at which the disciple leaves his nets and follows him. 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.
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 his 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.
The love of God is still free. You still do not have to earn it. But before accepting the free gift, you should be aware that there is a cost that comes later. Forgiveness of sins is just the beginning, it is followed by a call to go and sin no more. Being united to God through Christ is also just the beginning; it is followed by a call to redefine all of your commitments in the light of that relationship.