What is sanctification, and how is it related to our union with Christ?
Orientation
The struggle to become holy through our own moral effort only increases our awareness of sin and leads to futility.
- Law-keeping and moral performance cannot sanctify us.
- Trying to 'clean up' our own sin leaves us overwhelmed and aware of failure.
- This approach abandons the rest and assurance of our sonship in Christ.
For I know that in me (that is, in my flesh,) dwelleth no good thing: for to will is present with me; but how to perform that which is good I find not. For the good that I would I do not: but the evil which I would not, that I do. (Romans 7:18-19)
— Romans 7:18-19
Clarification
Sanctification is not primarily about eradicating sin but about God filling the believer with the presence of Christ.
- Holiness is the manifestation and indwelling of Christ within us.
- God's purpose is not just to clean us up, but to fill us with His Son.
- This transformation is the result of God's action, not our incremental self-improvement.
And ye know that he was manifested to take away our sins; and in him is no sin. (1 John 3:5)
— 1 John 3:5
Structure
Sanctification is secured by Christ's sacrifice and applied through our union with Him, typified by the Old Testament burnt offering.
- The burnt offering's blood sanctified the altar, making all that touched it holy, regardless of intrinsic worth.
- The ashes and water from the offering point to Christ's finished work removing death and the Spirit's living water bringing cleansing.
- Our union with Christ means His devotion, obedience, and sacrificial love become the basis of our holiness.
All the males among the children of Aaron shall eat of it. It shall be a statute for ever in your generations concerning the offerings of the LORD made by fire: every one that toucheth them shall be holy. (Leviticus 6:18)
— Leviticus 6:18
Weight-Bearing Prose
Sanctification is God’s work of filling believers with Christ’s presence. It is not a human project. The Pauline category is clear: the law was powerless, serving only to increase the trespass (Romans 5:20). Human effort to achieve holiness through law-keeping results in the accumulation and heightened awareness of sin (Romans 7). The counter-position of moral performance is a return to the flesh and abandons the inheritance secured in Christ.
The true basis is union with Christ, revealed in the type of the burnt offering. Christ’s blood sanctifies; His sacrifice imparts holiness to us by virtue of our contact with Him, not our intrinsic worth. He condemned sin in His flesh on the cross (Romans 8:3), providing the ‘fire’ that consumes what is dead. The living water—the Spirit received by faith—is the fountain that washes and satisfies (John 4:14; 7:38-39). Thus, sanctification is the manifestation of Christ in the believer (Colossians 1:27), transforming us into His image (2 Corinthians 3:18) and emitting a fragrance pleasing to God. Holiness is redefined as the presence of Christ, not mere sinlessness.
Integration
Your sanctification is as secure as your justification, for both are found in the same Person: Christ. He is your sanctification (1 Corinthians 1:30). There is no pressure to advance or to manufacture a holiness He has already provided. The Spirit within you is the guarantee, the living water, the renewing presence. Your part is not to strive, but to receive and enjoy the Christ who dwells in you. This is your assurance. The work is God’s, from start to finish—He fills you with Christ. Rest here. Your holiness is His presence, and His presence is your life and joy. You are a vessel containing Christ, and that is enough.