Cheap grace means grace as a doctrine, a principle, a system. 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. 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 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.
All for sin could not atone. 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 is what we mean by cheap grace, the grace which amounts to the justification of sin without the justification of the repentant sinner who departs from sin and from whom sin departs. Cheap grace is not the kind of forgiveness of sin which frees us from the toils of sin. Cheap grace is the grace we bestow on ourselves.