How does a Christian grow holy?

What the Bible says

In Scripture the basic sense of "holy" is not moral perfection but "set apart, belonging to God." The Bible says that holiness is first of all God's work. In Leviticus God commands Israel to keep his statutes and adds, "I am the LORD who sanctifies you" (Lev 20:8). The one who commands is also the one who accomplishes. After listing the old sins of the Corinthians, Paul goes on:

And that is what some of you were. But you were washed, you were sanctified, you were justified, in the name of the Lord Jesus Christ and by the Spirit of our God.

1 Cor 6:11

"Sanctified" is spoken of here as something already received. Those who belong to Christ have already been set apart. Hebrews says that by a single offering Christ "has made perfect for all time those who are being sanctified" (Heb 10:14), and the same letter commands, "Pursue peace with everyone, as well as holiness" (Heb 12:14). So Scripture speaks of being already made holy and of being made holy: given to God in standing, growing into it in life.

This growth is God's will (1 Thess 4:3), and Paul prays that God himself will do it.

Now may the God of peace Himself sanctify you completely, and may your entire spirit, soul, and body be kept blameless at the coming of our Lord Jesus Christ.

1 Thess 5:23

What does the believer do? Philippians puts God's work and our response in one sentence.

continue to work out your salvation with fear and trembling. For it is God who works in you to will and to act on behalf of His good purpose.

Phil 2:12-13

"Work out your salvation" does not mean earning it but living out what has been given, by the power of the God who "works in you." Jesus teaches the same through the vine: "apart from Me you can do nothing" (John 15:5).

What does the change look like? Paul writes:

And we, who with unveiled faces all reflect the glory of the Lord, are being transformed into His image with intensifying glory, which comes from the Lord, who is the Spirit.

2 Cor 3:18

As we look to Christ we are changed into his likeness, and the fruit is the fruit of the Spirit.

But the fruit of the Spirit is love, joy, peace, patience, kindness, goodness, faithfulness, gentleness, and self-control.

Gal 5:22-23

Fruit grows from a root. Yet the Bible never says the struggle is easy. In Romans 7 Paul confesses, "I keep on doing the evil I do not want to do" (Rom 7:19), and cries, "What a wretched man I am!" (Rom 7:24). The answer comes in the next verse: "Thanks be to God, through Jesus Christ our Lord!" (Rom 7:25). In Philippians 3:12-14 he says he has not yet been made perfect but presses on.

The church's witness

The church has seen holiness grow through the "means of grace." The first church devoted itself to the apostles' teaching, fellowship, the breaking of bread and prayer (Acts 2:42). Jesus prayed to the Father, "Sanctify them by the truth; Your word is truth" (John 17:17). On that verse Augustine writes that "the sanctified have still to grow in sanctity" by the help of God's grace Augustine. On John 15:5 he notes of the branch apart from the vine, "He does not say, you can do little." Augustine

The Westminster Shorter Catechism calls it a work of God's free grace by which we are enabled more and more to die to sin and live to righteousness Westminster Shorter Catechism, Q. 35.

Traditions differ over how far this change goes on earth.

The Reformed emphasis is that a believer is freed from sin's dominion at union with Christ, but the change of the whole life is progressive until death, and sin is not entirely removed in this life. Matthew Henry, on 1 Thessalonians 5:23, says "the best are sanctified but in part while in this world" Matthew Henry. Reformed readers commonly take Romans 7 as the struggle of a regenerate person, as Henry does: one who "had it greatly at heart, not to walk so" Matthew Henry. Many Greek Fathers, Wesley and many modern scholars read it instead as life under the law without the Spirit; the passage has long been disputed.

The Wesleyan tradition teaches that God can make believers "perfect" in love in this life. This does not mean sinlessness or freedom from mistakes, but a heart filled with love for God and neighbour and freed from deliberate sin. Wesley taught that it is received by faith as a gift. Reformed Christians think this goes beyond what Scripture promises; Wesleyans answer that God commands this love and Paul prays that God will "sanctify you completely" (1 Thess 5:23), so expecting less lowers hope. Both take seriously "If we say we have no sin, we deceive ourselves" (1 John 1:8).

The Eastern Orthodox call the goal of salvation theosis, "deification." It does not mean that humans become God but that by grace they share in God's life and love. They rely on 2 Peter 1:4, that we may "become partakers of the divine nature," and follow Athanasius, who taught that the Word became human so that we might be made divine, that is, share by grace in God's life Athanasius, On the Incarnation. What all share is that sanctification is the work of grace and the Spirit, a growing likeness to Christ.

In the original languages

"To sanctify" is hagiazo (ἁγιάζω); its noun is hagiasmos (ἁγιασμός). It means "to set apart and give to God." The Old Testament Hebrew qadash (קָדַשׁ) has the same idea. A tabernacle vessel is holy not because it is morally excellent but because it belongs to God and is set apart. So the New Testament calls believers "saints," "holy ones," because they belong to God, not because they are finished.

The "work out" of Philippians 2:12 is katergazomai (κατεργάζομαι), "to bring about, carry through." Most readers take it as "live out what you have received," not "work in order to be saved."

Common objections

"If Christians are really changed by the Spirit, why is there so much hypocrisy and sin in the church? Christians are no better than anyone else." This objection must be taken most seriously, because the claim that the Spirit changes people can be tested. The church's failures have been plain in history and are plain now. But the Bible does not say that Christians are already better people; it says sanctification is slow, partial and uneven. A Christian is not a finished person but one being healed. People begin from different places, and change often shows in small things such as patience, forgiveness and honesty.

"Does stressing holiness not lead to legalism and condemnation? If God accepts us by grace, why tell us to try?" It has happened. But the Bible's order is the reverse. First comes the declaration that "there is now no condemnation for those who are in Christ Jesus" (Rom 8:1), and holiness follows. Holiness is not the price of being accepted but the response of one already accepted. And since "He is faithful and just to forgive us our sins" (1 John 1:9), failure is a reason to return, not to give up. Sanctification becomes legalism when it becomes effort outside grace.

Going further

Before it is an exhortation, sanctification is a promise. What God has begun he completes. Paul is confident that "He who began a good work in you will carry it on to completion until the day of Christ Jesus" (Phil 1:6). So a believer need neither despair at failure nor boast at progress.

You might ask yourself: Have I thought of growth as my effort, or as remaining in the vine? What place do word, prayer and fellowship have in my life now?

To read further, see What is justification?, Who is the Holy Spirit? and How should we live?