I had the privilege of leading a young man in my church to faith in Jesus when he was in the eighth grade. He grew up in a Christian home and was a consistent church goer, attending church each Sunday and actively participating in our church’s youth group. After leading him to faith in Jesus, I began discipling him. A few months into his discipleship, he asked me, “what is sexual immorality? What does it mean?” I was shocked. How could a young man who grew up in the church not know the meaning of sexual immorality? It was at that point I began realizing that not only did my church not teach on sexual ethics, but many churches and many denominations do not teach on sexual ethics and, specifically, sexual immorality.
Sexual immorality according to the Bible can best be understood as unsanctioned sexual conduct and is derived from the Greek term πορνεία. For Christians, God is the one who determines what is sanctioned sexual conduct and what is unsanctioned sexual conduct. The place God has revealed what is sanctioned and unsanctioned sexual conduct is in the Bible.
Thus, to understand what conduct is considered sexual immorality, we must turn to the Bible and determine what sexual conduct is prohibited. The following is a brief survey of all sexual conduct that the Bible considers unsanctioned (i.e., sexual immorality).
1. Heterosexual Sexual Conduct Outside of Marriage
The best two passages that speak toward sexual conduct outside of marriage are 1 Corinthians 7:1–5 and 7:8–9. The topic of 1 Corinthians 7:1–5 is sexual contact or “touching” (ἅπτω), which the ESV rightly translates as “sexual relations” (v 1). The idea is any kind of sexual contact, not just intercourse. Paul equates sexual relations/contact outside of marriage with “sexual immorality” (πορνεία) in verses 2–4. Paul’s argument is that to avoid the temptation of sexual immorality (i.e., to avoid unsanctioned sexual relations/contact), a person should get married. Thus, Paul limits all sexual relations/conduct to marriage between one woman and one man. Any kind of sexual conduct that happens outside of a heterosexual marriage, including ‘fooling around,’ is considered sexual immorality.
In 1 Corinthians 7:8–9, Paul is still on the topic of sexual relations. Here he focuses on the unmarried and the widows. Paul’s charge to them is that they should marry if they cannot exercise self-control. The context is clear that the self-control refers to sexual conduct. If an unmarried person or a widow cannot exercise self-control in the sexual sphere, he or she should marry. Paul’s reasoning is because “it is better to marry than to burn with passion” (1 Cor 7:9). Similarly to 1 Corinthians 7:1–5, Paul limits all sexual relations/conduct to heterosexual marriage.
“it is better to marry than to burn with passion”
1 CORINTHIANS 7:9
Heterosexual sexual conduct outside of marriage is one of the greatest struggles for young Christians in the West today. Many Christians have convinced themselves that ‘fooling around’ is fine as long as they are not engaged in sexual intercourse. This, however, is not true. The church needs to stand up denounce all forms of heterosexual sexual conduct outside of marriage.
2. Sex with Prostitutes
Sex with prostitutes is a sub-category of heterosexual conduct outside of marriage. The apostle Paul explicitly condemns sex with prostitutes in 1 Corinthians 6:12–20, saying “Shall I then take the members of Christ and make them members of a prostitute? Never!” (1 Cor 6:15).
“Shall I then take the members of Christ and make them members of a prostitute? Never!”
1 CORINTHIANS 6:15
3. Orgies
Orgies is another sub-category of heterosexual conduct outside of marriage. Orgies refers to having sex with multiple people at the same time or one right after the other. The apostle Paul includes orgies in his list of “works of the flesh” (Gal 5:19–21; cf. Rom 13:13). Also included in Galatians 5:19–21 and Romans 13:13 are sexual immorality and sensuality.
4. Lust
In Matthew 5:27–28, Jesus equates lusting after someone who is not your spouse as equivalent to adultery. Lust is thinking sexually about a person and sexually desiring a person who is not your spouse. To think sexually about a person who is not one’s spouse is the same as actually engaging in sexual conduct with that person in the eyes of Jesus and is, thus, the equivalent of committing adultery. The only person you are allowed to think about sexually is your spouse because, by definition, thinking sexually about and sexually desiring one’s spouse is not lust. Because of Jesus’ prohibition against lust, pornography is also prohibited because pornography’s sole purpose is to cause others to lust (for a more detailed analysis of pornography, check out my article on whether or not Christians should watch pornography). Further, masturbation is prohibited because it is almost impossible not to lust after a person when masturbating (see my article on whether or not Christians should masturbate).
“You have heard that it was said, ‘You shall not commit adultery.’ But I say to you that everyone who looks at a woman with lustful intent has already committed adultery with her in his heart.”
MATTHEW 5:27–28
5. Adultery
Adultery is when a married person engages in sexual conduct with a person who is not their spouse. There are many passages throughout the Bible that condemn adultery, such as Proverbs 6:20–7:27, Matthew 5:27–28, and 1 Corinthians 6:9–10. Most everyone in the West (and around the world) used to consider adultery as sexual immorality and a heinous act. Unfortunately, adultery is becoming more and more acceptable in the West. Open marriages are being promoted and glorified on social media, trading spouses (formerly called “swinging”) is becoming more prominent, and there are an ever increasing amount of websites that cater toward married people who wish to commit adultery, helping them engage in this immoral behaviour.
I am friends with a former pastor who was aware of a couple committing adultery in his church. When I became aware of it while hosting a revival in his church, I told him. He said he was aware and would handle it after the revival. Unfortunately, he never did. The man divorced his wife and married the woman with whom he was committing adultery, and most of the church attended and celebrated the adultery that led to the wedding. This should never happen in God’s church.
6. Homosexuality
Homosexuality is when a man engages in sexual conduct with another man or a woman engages in sexual conduct with another woman. Like adultery, the Bible is replete with passages condemning homosexuality and labelling it as sexual immorality, such as Leviticus 18:22, Romans 1:18–32, specifically verses 26–27, and 1 Corinthians 6:9–10. Also like adultery, most everyone in the West (and around the world) used to consider homosexuality as sexual immorality and a heinous act. Unfortunately, not only has the non-Christian culture embraced homosexuality as good and right, but so have many churches and whole denominations. For a more in-depth treatment on what the Bible says about homosexuality and why the arguments promoting it as good are flawed, see my posts entitled “Is Homosexuality a Sin” PART I and PART II.
“Or do you not know that the unrighteous will not inherit the kingdom of God? Do not be deceived: neither the sexually immoral, nor idolaters, nor adulterers, nor men who practice homosexuality, nor thieves, nor the greedy, nor drunkards, nor revilers, nor swindlers will inherit the kingdom of God.”
1 CORINTHIANS 6:9–10
7. Incest
Incest is when a person engages in sexual conduct with a close relative (Lev 18:6–18, 24–30; 1 Cor 5:1–12). The Lord considers incest depravity and an abomination. What God considers depraved and abominable never changes, regardless of what stage in salvation history a person is. Thankfully, Western culture is still against incest, so it isn’t too much of a problem in the Western church.
8. Bestiality
Bestiality is when a person engages in sexual conduct with an animal (Lev 18:23–30). The Lord considers bestiality depravity and an abomination. What God considers depraved and abominable never changes, regardless of what stage in salvation history a person is. I won’t say much about this topic here, but it is still practiced in the Western world. One simply needs to go to the internet (which I DON’T recommend you do).
9. Sex During Menstruation
Leviticus 18:19–30 labels having sex while the woman is menstruating as an abomination (also see Ezek 18:5–9). Like homosexuality, incest, and bestiality, what God considers depraved and abominable never changes, regardless of what stage in salvation history a person is. Thus, modern Christians should also abstain from sexual relations while the woman is menstruating.
10. Rape
Rape is non-consensual sex; it is when a male forces a female to have sex with him against her will. The Bible never speaks of a woman raping a man; only a man raping a woman. The clearest passage in the Bible that speaks against rape is Deuteronomy 22:25–29. Rape is denounced, but provisions are made for the rape of a virgin so that she is not left destitute, which is seen as a grace toward the virgin (vv 28–29). 2 Samuel 13:1–22 also depicts the rape of Tamar as wrong. Thankfully, rape is still considered sexual immorality and a heinous act in the West today.
11. Divorce and Remarriage for Unsanctioned Reasons
Divorce and remarriage for unsanctioned reasons may be the most surprising entry in this list of unsanctioned sexual conduct. However, it should be noted that Jesus equates divorce and remarriage for unsanctioned reasons with adultery in the following passages:
- A man divorcing his wife causes her to commit adultery, unless she has been unchaste (Matt 5:32)
- A man divorcing his wife and marrying another woman commits adultery (Matt 19:9; Mark 10:11–12; Luke 16:18)
- A man marrying a divorced woman commits adultery, regardless of whether he has been divorced or not (Matt 5:32; Luke 16:18)
- A woman divorcing her husband and marrying another man commits adultery (Mark 10:11–12)
- Paul agrees with the above (see 1 Cor 7:10–27, 39)
For a more in-depth treatment on what the Bible says about divorce and remarriage, see my posts “Are Christians Allowed to Divorce?” and “Are Christians Allowed to Remarry?”
Conclusion
According to the Bible, the following sexual conduct is prohibited and is considered sexual immorality: heterosexual sexual conduct outside of marriage, sex with prostitutes, orgies, lust, adultery, homosexuality, incest, bestiality, sex while the woman is menstruating, rape, and divorce and remarriage for unsanctioned reasons.
The big question for modern Christians is whether or not what the Bible says about unsanctioned sexual conduct is authoritative over our lives or not. In other words, should I avoid or engage in some or all of the above eleven prohibitions? The answer to this question depends on your philosophy and method for applying the Bible. For me, I believe that all Christians of all ages should avoid the above eleven prohibitions for two reasons. First, the above prohibitions that are mentioned in the New Testament are for disciples of Jesus, members of the church, and citizens of the kingdom of God. Since I am a disciple of Jesus, a member of the church, and a citizen of the kingdom of God, the prohibitions apply to me. Second, the above prohibitions that have only Old Testament references are considered abominations in the sight of God. Since God is immutable, what is considered an abomination prior to Jesus’ resurrection is considered an abomination after Jesus’ resurrection and is, thus, directly applicable to me as a disciple of Jesus and son of God.