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 is the sanctuary of God; it has to be protected from the world, and not thrown to the dogs. It is therefore the living word, the Word of God, which he speaks as it pleases him. 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."

p. 49. - Costly Grace