What Is Sanctification?

Q. 35: What is sanctification?
Answer: Sanctification is the work of God's free grace, whereby we are renewed in the whole man after the image of God, and are enabled more and more to die unto sin, and live unto righteousness. (WSC)

The word “sanctification” refers to being made holy. By nature we are corrupt, but by his grace we are restored on the inside, definitively in our conversion and progressively in our sanctification. In our conversion, we undergo a fundamental change which enables us to exercise faith in Christ. In our sanctification, this seed of new life grows and flourishes, transforming the whole person. As Colossians 3:9-10 says, “you have put off the old self with its practices and have put on the new self, which is being renewed in knowledge after the image of its Creator.” Notice it speaks of a definitive change in the past (“you have put off…put on”) and an ongoing work in the present (“which is being renewed”).

All those whom God declares righteous on the basis of Christ’s righteousness, he also makes righteous. While justification is a declaration which take full effect immediately, sanctification is a work which takes effects more and more throughout our lives. While all believers are equally and fully justified, we are unequal and unfinished in our sanctification in this life. Both justification and sanctification are fruits of Christ’s death and resurrection being applied to us by the Spirit.

The catechism notes that this sanctification encompasses the “whole man” - all our faculties are corrupted by sin and renewed by grace. We are told to “cleanse ourselves of every defilement of body and spirit, bringing holiness to completion in the fear of God” (2 Cor. 7:1). The catechism also notes that we are being renewed after the image of God (Eph. 4:24, Col. 3:10, Gen. 1:28). Human nature is being restored to display God’s glory as it was intended to so, in true knowledge, righteousness, holiness, and dominion. It also notes that there are two sides to sanctification - dying unto sin and living unto righteousness. As Ephesians 4:21-24 says, we are taught in Christ to “put off your old self, which belongs to your former manner of life and is corrupt through deceitful desires … and to put on the new self, created after the likeness of God in true righteousness and holiness.”