# What Is Sanctification? How God Makes You Holy Over Time

- Canonical: https://www.iamreborn.net/blog/what-is-sanctification
- Author: Daniel Ziedins (https://www.iamreborn.net/about-daniel-ziedins)
- Published: 2026-11-05
- Reading time: 3 minutes

## Short answer

Sanctification is the lifelong work by which God makes a believer holy in practice — more and more like Jesus in character, desires and actions — and the Bible calls it God's will for every Christian (1 Thessalonians 4:3). Justification is God's instant declaration that you are righteous in Christ; sanctification is the gradual change that follows; glorification is its completion. Believers are “perfected for all time” yet “being sanctified” (Hebrews 10:14). We work it out as God works in us (Philippians 2:12–13), through Scripture, prayer, the Holy Spirit, repentance, community and trials, and He will finish it (Philippians 1:6).

You trusted Jesus. You're forgiven. And yet the old habits, the short temper, the same struggles are still there. Is something wrong? Not necessarily. You may simply be in the middle of what the Bible calls **sanctification**.

> For this is the will of God, your sanctification.
>
> — 1 Thessalonians 4:3

## What sanctification means

To sanctify is to make holy — to set apart for God and make like Him. Sanctification is the work God does in a believer's life to make them more and more like Jesus in character, desires and actions.

## Three words that help

- **Justification** — the moment God declares you righteous because of Jesus. It's instant and complete. You can't be more justified than you are today (Romans 5:1).
- **Sanctification** — the lifelong process of being made holy in practice. It's gradual and ongoing.
- **Glorification** — the day God finishes the work and you are made perfectly like Christ (1 John 3:2).

Put simply: justification changes your _standing_; sanctification changes your _life_. Mixing them up causes two opposite problems — anxiety (thinking your acceptance depends on your progress) or apathy (thinking progress doesn't matter because you're accepted).

## Already holy — and becoming holy

> For by a single offering he has perfected for all time those who are being sanctified.
>
> — Hebrews 10:14

Look at the two halves of that verse. _Perfected for all time_ — that's what Jesus has already secured for you. _Being sanctified_ — that's what He's working out in you now. Both are true at once. You are holy in God's sight because of Christ, and you are becoming holy in daily life by His Spirit.

## Who does the work?

> Therefore, my beloved, as you have always obeyed, so now, not only as in my presence but much more in my absence, work out your own salvation with fear and trembling, for it is God who works in you, both to will and to work for his good pleasure.
>
> — Philippians 2:12–13

Paul holds both together. _Work out_ your salvation — you have a real part to play. _For it is God who works in you_ — and underneath your effort is His. You don't sit back and wait to become holy, and you don't white-knuckle your way there alone. You work because God is working.

> You don't work to be accepted. You work because God is already at work in you — and He finishes what He starts.

## How sanctification happens

> And we all, with unveiled face, beholding the glory of the Lord, are being transformed into the same image from one degree of glory to another. For this comes from the Lord who is the Spirit.
>
> — 2 Corinthians 3:18

We become like what we behold. As you keep looking at Jesus, the Spirit keeps changing you. God uses ordinary means to do it:

- **Scripture** — truth renews the mind (Romans 12:2; see [How To Renew Your Mind](https://www.iamreborn.net/blog/how-to-renew-your-mind)).
- **Prayer** — staying connected to the Vine (John 15:5).
- **The Holy Spirit** — who grows His fruit in you ([What Is The Fruit Of The Spirit?](https://www.iamreborn.net/blog/what-is-the-fruit-of-the-spirit)).
- **Confession and repentance** — turning quickly when you fall ([What Is Repentance?](https://www.iamreborn.net/blog/what-is-repentance)).
- **Community** — other believers who encourage and sharpen you (Hebrews 10:24–25).
- **Trials** — which produce endurance and character (Romans 5:3–4; James 1:2–4).

## When it feels slow

Sanctification is usually slower than we want and less dramatic than we expect. Growth often shows up in hindsight: you notice you're quicker to apologise, slower to anger, less enslaved to the thing that used to own you. Don't measure your progress by one bad week. Hold on to the promise:

> And I am sure of this, that he who began a good work in you will bring it to completion at the day of Jesus Christ.
>
> — Philippians 1:6

**Sanctification, in short**

- **Sanctification** is God making you holy — like Jesus — over a lifetime (1 Thessalonians 4:3).
- **Justification** changes your standing; **sanctification** changes your life.
- **Already and not yet:** perfected in Christ, being sanctified in practice (Hebrews 10:14).
- **God works and you work** (Philippians 2:12–13).
- **He uses** Scripture, prayer, the Spirit, repentance, community and trials.
- **He'll finish it** (Philippians 1:6).

[Start the First 30 Days](https://www.iamreborn.net/first-30-days) — One chapter, one question a day — the simplest place to begin growing.

## Frequently asked questions

### What is the difference between justification and sanctification?

Justification is God's one-time declaration that you are righteous because of Jesus — it changes your standing and is complete. Sanctification is the ongoing process of being made holy in daily life — it changes your character over time.

### Is sanctification God's work or mine?

Both. Paul says “work out your own salvation… for it is God who works in you” (Philippians 2:12–13). You make real effort, empowered and undergirded by God's work in you through the Holy Spirit.

### How does sanctification happen?

Through ordinary means God uses: Scripture renewing the mind, prayer, the Holy Spirit's fruit, confession and repentance, Christian community and trials. As we behold the Lord, we are transformed into His image (2 Corinthians 3:18).

### Why does growing as a Christian feel so slow?

Sanctification is lifelong and often only visible in hindsight. God promises that He who began a good work in you will bring it to completion (Philippians 1:6).

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From the Reborn Journal at I AM REBORN — https://www.iamreborn.net/blog/what-is-sanctification