Why do we need salvation? Pt 9: Sanctification
1 Corinthians 6:9a, 11 9Or do you not know that wrongdoers will not inherit the kingdom of God?... 11And that is what some of you were. But you were washed, you were sanctified, sanctified, you were justified in the name of the Lord Jesus Christ and by the Spirit of our God.
Romans 6:22-23 22But now that you have been set free from sin and have become slaves of God, the benefit you reap leads to holiness, and the result is eternal life. 23For the wages of sin is death, but the gift of God is eternal life in Christ Jesus our Lord.
1 Thessalonians 4:3 3It is God’s will that you should be sanctified: that you should avoid sexual immorality; 4that each of you should learn to control your own body in a way that is holy and honorable, 5not in passionate lust like the pagans, who do not know God; 6and that in this matter no one should wrong or take advantage of a brother or sister. The Lord will punish all those who commit such sins, as we told you and warned you before. 7For God did not call us to be impure, but to live a holy life. 8Therefore, anyone who rejects this instruction does not reject a human being but God, the very God who gives you his Holy Spirit.
Hebrews 12:14-15 14Make every effort to live in peace with everyone and to be holy; without holiness no one will see the Lord. 15See to it that no one falls short of the grace of God and that no bitter root grows up to cause trouble and defile many.
1 Peter 1:15-16 15But just as he who called you is holy, so be holy in all you do; 16for it is written: “Be holy, because I am holy.”
Sanctification: Washed, Set Apart, and Called to Holiness
Sanctification is a process of growing closer to God and becoming more like Jesus. It’s not just a one-time event; it’s an ongoing journey we share together as believers. When we think of sanctification, we think of being set apart for God’s purpose, allowing the Holy Spirit to work within us, and transforming us into the image of Christ. Many of us may not fully understand the importance of sanctification in our lives, but it shapes our character and strengthens our faith.
In our walk with God, we recognize that sanctification calls us to be holy. This means setting ourselves apart for God’s purpose in our lives and striving to live in a way that reflects His character. God desires that we embody holiness, which can lead us into a deeper relationship with Him. When we focus on holiness, we begin to see our lives transform, and we model the love of Christ to those around us. It is vital to understand the role of the Holy Spirit in our lives. The Holy Spirit empowers us and leads us toward holiness, reminding us of God’s teachings and urging us to grow closer to Him. Without the Holy Spirit, our efforts in sanctification would be empty.
Sinners can’t inherit the Kingdom of God
When Paul wrote to the Corinthians, he was painfully aware of the culture they lived in. Corinth was a bustling city, wealthy, diverse, but notorious for immorality. So, he does not mince words in 1 Corinthians 6:9:
"Do you not know that wrongdoers will not inherit the kingdom of God? Do not be deceived: neither the sexually immoral nor idolaters nor adulterers nor men who have sex with men nor thieves nor the greedy nor drunkards nor slanderers nor swindlers will inherit the kingdom of God."
That is a sobering list. Notice how Paul says, “Do not be deceived.” He knows how easy it is for believers to excuse certain sins while condemning others. It’s almost as if he’s pulling back the curtain to show that sin in any form is incompatible with God’s Kingdom. The message is clear: sin excludes us from life with God.
Now, that can sound crushing. Who among us has not been greedy at some point, or slandered someone, or fallen into temptation? Paul’s warning highlights humanity’s universal problem—our nature is corrupted by sin. Sanctification begins here: with a clear-eyed recognition that sin is destructive, and it disqualifies us from God’s Kingdom. It forces us to face reality: if left to ourselves, we cannot live in fellowship with a holy God.1
But this recognition is not intended to drive us to despair—it is meant to drive us to Christ. The bad news sets the stage for the good news, because Paul doesn’t stop with this list. Just two verses later, he reminds the Corinthians that something has already happened to them that changed their story forever.
But the gift of God washes us clean
After that heavy warning, Paul pivots in verse 11:
"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."
Notice the past tense—“you were.” Paul acknowledges that some of his readers once lived in those sins, but something decisive has changed. Through Christ, they have been washed. Their old record has been cleansed. They have been sanctified—set apart as God’s people. They have been justified—declared righteous in God’s sight. Paul uses these verbs like courtroom evidence. He’s saying: “Yes, you once lived in sin. But that’s not your identity anymore. God’s Spirit has done something new in you.” This is where sanctification starts—not with our effort, but with God’s action.
Romans 6 echoes this same theme. Paul contrasts sin’s outcome with God’s gift:
"But now that you have been set free from sin and have become slaves of God, the benefit you reap leads to holiness, and the result is eternal life. For the wages of sin is death, but the gift of God is eternal life in Christ Jesus our Lord" (Romans 6:22–23).
Sanctification, then, is rooted in grace. We don’t purify ourselves to earn God’s love. Rather, God in Christ takes the initiative—He frees us from sin, and then His Spirit begins a lifelong process of shaping us into holiness. Think of it like adoption. A child is not adopted because they have earned the right family. The act of adoption itself establishes the relationship. But once that child is part of the family, their new identity reshapes their life. In the same way, sanctification flows out of the gift of being “washed” and “set free.”
So that we can learn sanctification
If sanctification begins with God’s work, it continues with our cooperation. Paul reminds the Thessalonian church:
"It is God’s will that you should be sanctified: that you should avoid sexual immorality; that each of you should learn to control your own body in a way that is holy and honorable" (1 Thessalonians 4:3–4).
Notice the phrase “learn to control.” Sanctification is not automatic. God gives His Spirit, but we must learn obedience, discipline, and surrender. This means that sanctification has both a divine side (God working in us) and a human side (our daily choices). Think about learning a musical instrument. The gift of the instrument might be free, but becoming skilled requires practice, perseverance, and sometimes correction. Sanctification works like that. The Spirit gives us the new heart, but then He teaches us to walk in holiness one step at a time. And Paul calls this “God’s will.” People often ask, “What’s God’s will for my life?” Paul’s answer is striking: before career decisions, before life direction—God’s will is your sanctification. Holiness is not an optional extra for the “super spiritual.” It is the basic expectation for every follower of Christ.2
And live at peace with God and people
Sanctification is not just private spirituality. It overflows into how we treat others. Holiness cannot be separated from love, forgiveness, and peace. In fact, bitterness and division can defile not just one person, but whole communities. Hebrews 12:14-15 teaches two vital truths. First, holiness is necessary to see the Lord. That’s not legalism; it’s a reality. You cannot cling to sin and enjoy fellowship with a holy God. Second, holiness is relational—it means putting away bitterness, seeking reconciliation, and striving for peace.
Sanctification is not just about avoiding obvious sins. It’s also about cultivating a heart that seeks peace with others. Think of how radical that was for the first-century believers—many of them were Jews and Gentiles learning to share life together in Christ. Their unity in holiness was a testimony to the watching world. Today, this principle still holds. Sanctification shows itself not only in personal purity but in communal love. When believers live at peace with one another, forgiving and bearing with each other, they reflect God’s sanctifying grace.
Becoming holy as Jesus is holy
The call to sanctification reaches its climax in Peter’s words:
"But just as he who called you is holy, so be holy in all you do; for it is written: 'Be holy, because I am holy'" (1 Peter 1:15–16).
Here the standard of holiness is not cultural norms, not religious tradition, not even our best efforts. The standard is God Himself. That feels impossibly high! Yet it’s not meant to crush us; it’s meant to lift our eyes. Sanctification is ultimately about reflecting Christ’s character.
Peter roots this command in God’s calling. The God who called us out of darkness into His marvelous light (1 Peter 2:9) also equips us to live as His holy people. Holiness, then, is not drudgery—it is our new identity.
Imagine a stained-glass window. On its own, the glass looks dull and colorless. But when sunlight shines through, it glows with beauty. In the same way, when the holiness of Christ shines through us, His beauty is revealed to the world. That is sanctification—Christ’s holiness reflected in the lives of His people.
What about me?
So, let’s put it all together.
Without Christ, we are sinners who cannot inherit God’s Kingdom (1 Corinthians 6:9).
But by His grace, God washes us clean and sets us free (1 Corinthians 6:11; Romans 6:22–23).
He then calls us to learn sanctification through daily obedience (1 Thessalonians 4:3).
This holiness is relational—it means living at peace with God and with others (Hebrews 12:14–15).
And the ultimate goal is to become holy as Jesus is holy (1 Peter 1:15–16).
Sanctification is both a gift and a calling. It begins with God’s action, continues with our cooperation, and culminates in Christlikeness. It is not perfection we achieve overnight, but a lifelong journey of being made more like Jesus.
The gospel promise is that what God begins, He will also finish (Philippians 1:6). Sanctification may feel slow, and we may stumble, but the Spirit keeps shaping us. And one day, when we see Christ face to face, the process will be complete—we shall be like Him, for we shall see Him as He is (1 John 3:2).
That is the hope and joy of sanctification: not merely trying harder, but being transformed by the grace of God into the likeness of Christ.
Footnotes
Gordon D. Fee, The First Epistle to the Corinthians (Grand Rapids: Eerdmans, 1987), 243.
F. F. Bruce, 1 and 2 Thessalonians (Word Biblical Commentary, Vol. 45; Waco: Word Books, 1982), 82.