Short answer: Porneia (Greek: πορνεία) is the New Testament's broad word for sexual immorality, meaning any sexual activity outside the marriage of one man and one woman. It covers fornication, adultery, incest and other illicit sexual behaviour, and some Bibles simply translate it "fornication" while the NIV usually says "sexual immorality." It is a sin, but it is a forgivable one, and Christ offers cleansing to everyone who repents.
In This Article
If you are reading a verse in the King James or the NASB and it says "fornication," and then reading the NIV and finding "sexual immorality," it is natural to wonder whether they are describing the same thing. They are. Behind both English words sits one Greek word, porneia, and getting a grip on it clears up a lot of confusion about what the New Testament actually forbids.
This article explains where the word comes from, what it covers, how Jesus and Paul used it, and what it means for you today. I will keep it plain and pastoral, and I will be careful where good Christians read a passage differently.
What Does Porneia Mean In The Bible?
Porneia is a Greek noun that the New Testament writers use for illicit sexual activity. It appears roughly two dozen times in the New Testament, along with related words such as pornos (a sexually immoral person) and porneuo (to commit sexual immorality). Translators have not handled it the same way. The NASB and the KJV traditionally use "fornication," while the NIV prefers "sexual immorality," and occasionally just "immorality."
The important thing to see is that porneia is an umbrella term. The New Testament often lists it beside other sins without stopping to define it, because its first readers already knew what it covered. It was a general category, and it pointed back to the sexual boundaries set out in the Old Testament, especially in Leviticus 18. The early church applied that same standard to Gentile believers. When the Jerusalem council wrote to them, sexual immorality was on the short list of things to avoid:
abstain from food polluted by idols, from sexual immorality
Acts 15:20 (NIV)
For a fuller treatment of the term in English, see What Is Sexual Immorality According To The Bible?
What Is The Biblical Definition Of Fornication?
In everyday use, fornication means consensual sex between people who are not married to each other. That is the narrower sense, and it is how most English readers hear the word. The Bible's design is that sexual union belongs inside the covenant of marriage, and the writer of Hebrews puts it directly:
Marriage should be honored by all, and the marriage bed kept pure, for God will judge the adulterer and all the sexually immoral.
Hebrews 13:4 (NIV)
So fornication is one form of porneia, and porneia is the larger category. Not every use of the Greek word should be read as "premarital sex" alone. You can read the narrower question in Is Premarital Sex A Sin In The Bible? and the related question of living together.
Examples Of Porneia In Scripture
People often ask for examples, so here is what the text itself names or implies:
- Sex before or outside marriage (fornication).
- Adultery, sex with someone else's spouse. See Is Adultery A Sin In The Bible?
- Incest. Paul rebuked the Corinthian church in 1 Corinthians 5:1 for tolerating it, and called it a kind of immorality that even pagans did not tolerate. Our article on incest looks at the Old Testament laws.
- Prostitution. The related word pornos is used of those who use prostitutes, as in 1 Corinthians 6:15-16.
- Other forbidden sexual acts named in Leviticus 18 and elsewhere. See What Sexual Activities Does The Bible Forbid? and Examples Of Sexual Sin In The Bible.
Is Kissing Fornication In The Bible?
No. The Bible never calls a kiss fornication, and kissing as a greeting and as affection runs through Scripture. The deeper question is the one Jesus put his finger on: what is happening in the heart? Kissing can be innocent, or it can be the start of something that leads past the boundaries, or it can be lustful in itself. I would encourage young couples to think of it as a path with a direction, and to set limits before they are in the moment. I have given that more space in Is Kissing Or Making Out A Sin In The Bible?
What Did Jesus Say About Fornication?
Jesus raised the bar from outward behaviour to inward desire. In the Sermon on the Mount he taught that the commandment against adultery reaches into the heart:
But I tell you that anyone who looks at a woman lustfully has already committed adultery with her in his heart.
Matthew 5:28 (NIV)
He also listed sexual immorality among the things that come out of a defiled heart in Matthew 15:19, and the word there is porneia. And in his teaching on divorce, Matthew 19:9, he makes an exception for "sexual immorality," again porneia. Christians have differed over exactly what that exception covers, and I address it in Is Divorce A Sin In The Bible? For lust itself, see Is Lust A Sin In The Bible?
Notice also that Jesus did not deal with sinners in this area with contempt. He told the woman caught in adultery that he did not condemn her, and then to leave her life of sin (John 8:11). Truth and mercy came together.
Why Is Fornication A Sin Against The Body?
Paul gives the clearest answer in 1 Corinthians 6, where he is correcting a church that treated sex as a casual appetite.
Flee from sexual immorality. All other sins a person commits are outside the body, but whoever sins sexually, sins against their own body.
1 Corinthians 6:18 (NIV)
His reasoning is that sex is not merely physical. It joins two people (1 Corinthians 6:16), and the believer's body belongs to Christ and is a temple of the Holy Spirit. Sexual sin therefore touches the whole person in a way that few other sins do. These commands are not meant to take pleasure from us. They protect us from harm, and the aching regret that follows casual intimacy shows how right the design is.
Is Fornication A Forgivable Sin?
Yes, without question. Fornication is not the unforgivable sin. Paul told the Corinthians, who included former adulterers and the sexually immoral, that they had been washed, sanctified and justified in the name of Jesus (1 Corinthians 6:9-11). John gives the promise plainly:
If we confess our sins, he is faithful and just and will forgive us our sins and purify us from all unrighteousness.
1 John 1:9 (NIV)
Forgiveness does not erase every consequence, and repentance means turning away, not just feeling sorry. But the door is open. If you want to know how to take that step, read How To Repent, and for the larger question see Does God Forgive All Sins?
Key Bible Verses About Porneia And Sexual Immorality
- 1 Corinthians 6:18: flee sexual immorality; it is a sin against your own body.
- Hebrews 13:4: keep the marriage bed pure.
- 1 Thessalonians 4:3: it is God's will that you avoid sexual immorality.
- Matthew 5:28: Jesus takes the standard to the heart.
- Acts 15:20: the early church lists sexual immorality to avoid.
- 1 Corinthians 5:1: Paul rebukes tolerated incest.
- 1 John 1:9: confession brings forgiveness and cleansing.
Frequently Asked Questions
What is the Greek word for fornication?
It is porneia (πορνεία). The related words pornos and porneuo describe a sexually immoral person and the act of committing sexual immorality. Older translations like the KJV and the NASB render porneia as fornication, while the NIV usually says sexual immorality.
What is the biblical definition of fornication?
Narrowly, it is sex between unmarried people. Broadly, the Greek word porneia covers any sexual activity outside the marriage covenant of one man and one woman, including adultery and incest. Scripture reserves sexual union for marriage.
Is kissing fornication in the Bible?
No. The Bible never calls kissing fornication. The issue is the heart and where it leads, which is why Jesus spoke about lust in Matthew 5:28. See Is Kissing Or Making Out A Sin? for more.
What did Jesus say about fornication?
He listed sexual immorality among the evil things that come from a defiled heart (Matthew 15:19) and taught that lustful looking is adultery of the heart. He also showed mercy to sinners, telling the woman caught in adultery that he did not condemn her and sending her to a new life.
Is fornication a forgivable sin?
Yes. Paul told former adulterers and the sexually immoral in Corinth that they had been washed, sanctified and justified in the name of Jesus. Confession and repentance bring forgiveness (1 John 1:9).
Why is fornication a sin against the body?
Paul says sexual sin is unique because sex unites two people, and the believer's body belongs to Christ as a temple of the Holy Spirit (1 Corinthians 6:15-19). It involves the whole person, not just a single act.
