Fornication-adultery
Short answer: In 1 Corinthians 6:12-20, Paul answers the Corinthians who treated sexual sin as spiritually irrelevant. He refuses their slogans: “All things are lawful for me,” but not all things are expedient, and the body is not for sexual immorality but for the Lord. Fornication and adultery are sins against Christ himself, because the believer is joined to him and indwelt by the Holy Spirit. The passage is not a rant against the body; it is a high view of the body. It connects sexual conduct to the resurrection, to union with Christ, and to redemption: the believer was bought with a price, so God is to be glorified in the body. That is the whole argument, and everything Paul applies flows from those facts.
The slogans the Corinthians were quoting
Paul opens with a phrase his readers clearly knew: “All things are lawful for me,” but not all things are expedient. He is not agreeing with the slogan; he is correcting it. The Corinthian church lived in a city saturated with temple prostitution and loose sexual ethics, and some had absorbed a Greek idea that the body was religiously irrelevant. Only the spirit mattered. Paul answers that this is false because the body is not religiously neutral; it belongs to the Lord who redeemed it.
Notice Paul's second qualifier: “All things are lawful for me,” but I will not be brought under the power of anything. Christian freedom is never permission to be enslaved. A man may argue that a practice is technically permitted, but if it masters him, he has lost the freedom he claims. Sexual sin is uniquely enslaving because it involves the body and creates a one-flesh bond. Paul's logic is pastoral, not merely legal.
The word expedient here means profitable, helpful, or fitting. Paul is asking a practical question: does this build me up in Christ or drag me away from him? Many of the Corinthians wanted a rule-free Christianity, but Paul will not allow freedom to become a cloak for sin. His first move is to dismantle the assumption that what happens in the body does not touch the soul.
Why Paul grounds sexual purity in the resurrection
Paul's argument in verses 13-14 is startling: the body is not for sexual immorality, but for the Lord, and the Lord for the body. Then he adds that God both raised the Lord and will raise us up by his power. This is the hinge of the whole passage. The Corinthians evidently thought the body was destined for destruction and therefore inconsequential. Paul says the opposite: God is going to raise this body, so what you do with it now matters.
This is a distinctly Christian argument. Pagan ethics often despised the body; some ascetics punished it. Paul honors it. The resurrection of the body means the physical, sexual dimension of a human being is not a disposable shell. If God intends to raise the body, then the body's present conduct belongs to the future he is preparing. Verse 14 is not a side note; it is the foundation under everything Paul commands.
The logic runs like this: the Lord was raised bodily, and we will be raised bodily by the same power. Since that is true, the body has a permanent destiny. Sexual sin uses the body for something contrary to that destiny. Paul will not let the Corinthians spiritualize the gospel into a message that has no grip on the flesh. Resurrection hope produces bodily holiness.
Joined to Christ, not merely instructed by him
In verses 15-17 Paul uses the strongest possible language: the believer's body is a member of Christ. He asks whether one should take the members of Christ and make them members of a prostitute. He then says that whoever is joined to a prostitute is one body with her, quoting the Genesis language that the two become one flesh. The union is not legal trivia; it is a real one-flesh bond.
Paul contrasts that with union with Christ: whoever is joined to the Lord is one spirit. Here is the theological heart of the passage. Christian ethics is not primarily a list of prohibitions; it is a question of belonging. The Corinthians asked whether a particular act was allowed. Paul asks who you are united to. If you are joined to Christ, then sexual union with someone outside that bond is a contradiction of your identity, not just a rule violation.
Notice that Paul does not say the body is evil and the spirit is good. He says the two unions are incompatible. The sin is not that sex is dirty; the sin is that it creates a union where no such union belongs. This is why Paul treats fornication with a severity he does not apply to every sin. The body is not a tool you loan out; it is the sphere of your union with Christ.
The sin against one's own body
Verse 18 is often quoted and often misunderstood: flee sexual immorality. Every other sin a person commits is outside the body, Paul says, but the sexually immoral person sins against his own body. He is not ranking sins into a hierarchy of unforgivables. He is describing what fornication actually does. It defiles the very self that is being offered to God. This is why his first instruction is flight, not debate. Flee. Do not stand and negotiate.
Paul's realism is worth noting. He does not tell the Corinthians to manage temptation through willpower or to prove their strength by staying near it. He tells them to run. That is not weakness; it is wisdom. The command assumes that sexual temptation is powerful and that the safest response is distance. In a culture that treats sexual expression as identity, Paul's counsel sounds severe. In fact it is protective.
It is also compassionate. Paul is writing to people who had already suffered the consequences of sexual chaos: broken unions, disordered desires, a divided conscience. His command is not the coldness of a moralist. It is the instruction of a pastor who knows where these roads end. Proverbs 6:20-35 makes the same case from the Old Testament, warning that the one who commits adultery destroys himself. Paul's theology and Israel's wisdom agree.
Is your body really not your own?
Verses 19-20 answer the question decisively: do you not know that your body is a temple of the Holy Spirit within you, whom you have from God? And you are not your own, for you were bought with a price. So glorify God in your body. This is one of the richest statements of Christian identity in the New Testament. The Holy Spirit does not merely influence a believer from a distance; he dwells in the body. That makes the body holy ground.
The phrase bought with a price points to the cross. Redemption is not a metaphor for self-improvement; it is a purchase. The believer was acquired by the blood of Christ. Therefore the body is not private property to be used at will. Modern readers may bristle at that, because autonomy is the air we breathe. Paul would say autonomy is precisely the illusion behind the Corinthian slogans. Freedom in Christ is not the freedom to do whatever I want with myself; it is freedom from sin for God.
This is why Paul's final command is positive: glorify God in your body. He does not end with a prohibition but with a purpose. Chastity is not the whole Christian life, but it is one place where the whole Christian life becomes visible. A body indwelt by the Spirit and bought by Christ has a reason to be holy that goes far beyond fear of punishment.
Fornication, adultery, and the words themselves
Scripture uses several terms, and it is worth being precise. Fornication (Greek porneia) ordinarily refers to sexual immorality broadly, including intercourse outside marriage. Adultery (moicheia) refers to sexual intercourse with someone other than one's spouse, which is why it violates a covenant. Hebrews 13:4 says, “Let marriage be held in honor among all, and let the bed be undefiled; but God will judge the sexually immoral and adulterers.” Both sins are named together there and placed under the same judgment.
Jesus intensifies the command rather than relaxing it. Matthew 5:27-30 says, “You have heard that it was said, ‘You shall not commit adultery;’” and then Jesus goes to the heart, addressing the lustful look. This is important when discussing fornication and adultery because it means the commandment was never merely about external acts. Paul's argument about the body runs in the same direction: the inner person and the outer act belong together.
Christians have differed on how to apply these texts in specific pastoral cases, and honesty requires saying so. What the texts do not permit is the claim that sexual sin is trivial, private, or spiritually neutral. The consistent witness of the Old Testament, Jesus, and Paul is that sexual conduct matters to God because the body matters to God. Whatever disputes exist about application, that baseline is not one of them.
Grace, repentance, and the person who has failed
Paul's severity must be read beside John 8:1-11, where a woman caught in adultery is brought before Jesus. The passage begins simply: “but Jesus went to the Mount of Olives.” In the account that follows, Jesus exposes the hypocrisy of the accusers and speaks to the woman without excusing her sin. The combination is exactly the biblical balance: no compromise with the sin, no contempt for the sinner.
This matters because teaching on sexual sin often produces two failures. One is license, which calls sin freedom. The other is cruelty, which treats the fallen as though Christ had not died for them. Paul himself writes to a church full of people who had been sexually immoral, and he does not tell them they are beyond repair. He tells them they were washed, sanctified, and justified in the name of the Lord Jesus. The call to purity is a call to live out a cleansing that has already been given.
So the pastoral application runs in two directions. To the one still practicing sexual sin, the call is to flee and to repent, without delay and without self-deception. To the one who has repented and still carries shame, the gospel says that the price paid for the body was the blood of Christ, and it was paid in full. Chastity is not penance; it is gratitude. The body that was bought is now offered back in worship.
Biblical fidelity check
What this passage establishes is clear: the believer's body belongs to the Lord, is indwelt by the Holy Spirit, and is destined for resurrection; therefore sexual immorality is incompatible with union with Christ, and the believer is called to glorify God in the body. What the passage does not establish is a hierarchy in which sexual sin is unforgivable, or a view that the body is inherently shameful. Paul's argument is the reverse of both. Nor does the passage give a detailed case law for every situation; it gives a theological foundation that must be applied with wisdom.
A common misreading treats verses 19-20 as though they said the body is insignificant and only the spirit matters. That is precisely the Corinthian error Paul is refuting. Another misreading turns the passage into permission for harshness toward those who have sinned sexually, as though the church had no room for the repentant. But Paul writes to a church that had been exactly that, and he calls them to holiness as people who were washed. The passage's own logic forbids both license and contempt.
Other passages that speak to 1 Corinthians 6:12-20
Paul's teaching here does not stand alone in his letters. His opening greetings and thanksgiving in this same letter establish the themes of calling, unity, and grace that he applies later to the body: see What Does 1 Corinthians 1:9 Mean? Context, Theology, and Application and What Does 1 Corinthians 1:10 Mean? Context, Theology, and Application. For the larger shape of the letter, 1 Corinthians 1: Called, United, and Boasting in the Lord traces how Paul addresses a divided, gifted, and morally confused church. And because chapter 10 continues the same argument about freedom, idolatry, and the body, 1 Corinthians 10: Warnings and Freedom is a natural next study.
Frequently asked questions
What is the difference between fornication and adultery in the Bible?
Adultery is sexual intercourse with someone other than one's spouse, and it therefore violates a marriage covenant. Fornication is the broader term for sexual immorality, including intercourse outside marriage. Hebrews 13:4 names both together when it says God will judge the sexually immoral and adulterers. The distinction matters because adultery adds covenant betrayal to sexual sin, but both are treated in Scripture as serious and both are answered by the same call to repentance and the same cleansing in Christ.
Does 1 Corinthians 6 teach that the body is unimportant?
No; it teaches the opposite. Paul says the body is for the Lord, that God will raise it, and that it is a temple of the Holy Spirit. His whole argument depends on the body being significant. The Corinthians were the ones treating the body as spiritually irrelevant, and Paul corrects them. He grounds holiness in the resurrection and the Spirit's indwelling, which gives the body permanent value rather than dismissing it.
Can someone who has committed sexual sin still be restored?
Yes. Paul writes to a church whose members had practiced sexual immorality and tells them they were washed, sanctified, and justified in the name of the Lord Jesus. John 8 shows Jesus dealing with a woman caught in adultery without excusing the sin and without condemning her to despair. The biblical pattern is repentance, forgiveness, and a renewed call to holiness, not permanent shame or exclusion from the people of God.
