What is sanctification?

Salvation & the GospelIn theological review

The short answer

Sanctification is God's ongoing work of making his people holy in real life, set apart for him and growing in likeness to Jesus. It begins at conversion, continues through the whole Christian life by the Holy Spirit, and involves real effort on the believer's part, effort God himself supplies and sustains.

The fuller answer

If justification is God's verdict, sanctification is God's renovation. The word means being made holy, set apart for God and increasingly like him in thought, desire and conduct. Paul can address ordinary, flawed Corinthian Christians as people already sanctified, because their position changed the moment they belonged to Christ. He can also command churches to pursue holiness daily, because their practice lags behind their position. Both are true at once, and holding them together keeps the doctrine healthy and honest.

For it is God’s will that you should be holy: You must abstain from sexual immorality;

1 Thessalonians 4:3 (BSB)

Paul is blunt about the direction of travel: God's will is your sanctification, worked out in concrete areas like sexual purity, honesty and love for other believers. At the end of the same letter he prays that God himself would sanctify his people through and through, body, soul and spirit. That pairing matters. Holiness is commanded, so we are responsible. Holiness is also God's own work, so we are dependent. Christian growth is never self help with religious language pasted on top of it.

because by a single offering He has made perfect for all time those who are being sanctified.

Hebrews 10:14 (BSB)

Hebrews holds the finished and the growing together in a single sentence: by one sacrifice Christ has made perfect forever those who are being made holy. The perfect standing is complete, because it rests on his offering. The being made holy is still under way, because we are not yet what we will be. That tension explains the Christian's odd experience of being fully accepted by God while still fighting sins he hates and grieving failures he confesses.

Therefore, my beloved, just as you have always obeyed, not only in my presence, but now even more in my absence, continue to work out your salvation with fear and trembling.

Philippians 2:12 (BSB)

The Westminster Shorter Catechism, question 35, describes sanctification as a work of God's free grace, by which we are renewed in the whole person after God's image, and enabled more and more to die to sin and live to righteousness. Philippians gives the method: work out your salvation with fear and trembling, for God works in you. Effort is real, but it rides on grace. The tools are ordinary: Scripture, prayer, worship, honest fellowship and obedience in small things.

Sources

Berean Standard Bible (BSB)
The Westminster Shorter Catechism (1647)

Review status: in-theological-review. Every Contend page passes a human theological review against the Statement of Faith before it is published as approved teaching. This section is in that queue.

Dig deeper

No answer here is a dead end. Follow the question on, test it in practice, or work the method yourself on the Dig deeper page.

What is justification?Justification is God's act of declaring sinners righteous on the basis of Christ's righteousness, received by faith alone. It is a legal verdict, not a process of becoming better: the justified person is pardoned, accepted and counted righteous before God, once and for all, because of Jesus.What is repentance?Repentance is a change of mind about sin and about God that turns into a change of direction. Peter's command joins both halves: repent and turn back, so that your sins may be wiped away. It is more than feeling sorry, which can evaporate by morning. It is agreeing with God about your sin, grieving it, and leaving it, trusting the mercy that meets you on the way back.What is faith?Faith is trusting God's word and God's Son with your whole weight. Hebrews defines it as the assurance of what we hope for and the certainty of what we do not see. It is not believing without evidence, and it is not mere agreement that something is true. It is the hand that receives what grace gives.I keep sinning. Am I still saved?Yes, a Christian who keeps struggling with sin can still be saved: John says claiming to be sinless is self deception, and he points sinners to confession and to Jesus as their advocate. The warning sign is not falling, but settling into sin without confession, grief, or resistance. God's discipline of his children is evidence of his fatherly love, not of his rejection.What does born again mean?To be born again is to be given new spiritual life by the Holy Spirit, so that a person turns to God, believes in Jesus and begins a genuinely new life. Jesus taught that this birth from above is necessary to see and enter the kingdom of God. It is God's work, received through faith.Bible Character: PaulThe Pharisee who persecuted the church until the risen Jesus stopped him on the Damascus road, and who became his apostle to the Gentiles, travelling the Roman world and writing many of the New Testament letters.