Sexual Relations

God links marriage and sexual intercourse.

We’ve looked at three of four interrelated factors regarding Biblical manhood and womanhood: marriage, single life, and male authority. The fourth is sexuality. God tightly links marriage and sexual intercourse. It’s an integral part of marriage and a great blessing, a physical expression of marital love and unity that helps maintain and strengthen that oneness. Wayne Grudem put it well:

The beauty of God’s created order for marriage finds expression in our sexuality within marriage. “Therefore a man shall leave his father and his mother and hold fast to his wife, and they shall become one flesh” (Gen. 2:24). From the beginning God designed our sexuality so that it reflects unity and differences and beauty all at the same time. As husband and wife, we are most attracted to the parts of each other that are the most different. Our deepest unity—physical and emotional and spiritual unity—comes at the point where we are most different. ¹

These blessings don’t apply outside the marriage bed. All sexual relations are to be confined to the marriage bed–there is no legitimate sexual expression outside of marriage. The writer of Hebrews is explicit:

Let marriage be held in honor among all, and let the marriage bed be undefiled, for God will judge the sexually immoral and adulterous. (Hebrews 13:4)

This strong statement reflects the truth that sexual activity is a two-edged sword. In its proper place, between husband and wife, it’s a blessing. Outside of marriage it’s evil and a cause for judgement.

The writer of Hebrews specifically condemns adultery and fornication. The prohibition against adultery is easy to understand–adultery, sexual relations between a married person and someone other than that person’s spouse, destroys marriages.

Adultery destroys the unity of the marriage and its reflection of the relationship of Christ with the church. Marriage is to be for life–its natural end is with the death of a spouse (1 Cor. 7:39). Jesus said the only legitimate basis for divorce is sexual immorality (Matt. 19:9).² This means that in some cases adultery kills the marriage. It breaks the union as much as if one spouse had died.

What about fornication, sexual relations between two non-married persons? Since married persons can’t commit fornication, why is it included in a verse about holding marriage in honor and keeping the marriage bed undefiled? It’s because all sexual activity outside marriage, regardless of one’s marital status, dishonors marriage and defiles the marriage bed. Adultery does it from within marriage and fornication from without.

Fornication dishonors marriage by unlinking sex from marriage. It’s a rejection of God’s setting marriage aside as a sanctified union, with associated blessings, between a man and a woman. Instead, fornicators illicitly seek sexual gratification apart from God’s plan. Fornication defiles the marital bed because when those who commit it later marry they carry the negative mental and physical effects of that sin into the marriage.

Sexual activity apart from marriage is destructive for other reasons as well. Paul says in 1 Corinthians that Christians who commit sexual immorality dishonor their relationship to Jesus as part of his body, the church:

…The body is not meant for sexual immorality, but for the Lord, and the Lord for the body. And God raised the Lord and will also raise us up by his power. Do you not know that your bodies are members of Christ? Shall I then take the members of Christ and make them members of a prostitute? Never! Or do you not know that he who is joined to a prostitute becomes one body with her? For, as it is written, “The two will become one flesh.” But he who is joined to the Lord becomes one spirit with him. (1 Corinthians 6:13b–17)

This is a deep teaching. Believers are part of the church, the body of Christ, united with Him in both body and spirit. Though our bodies will decay in the grave after death, they, like our spirits, are important to God. They’re so important that he will raise them during the resurrection, just as he raised Jesus. Using the analogy of two becoming one flesh in marriage, Paul says that when a Christian has intercourse with a prostitute he is joining the body of Christ with the prostitute.

He isn’t finished. In the following verses He adds that sexual immorality isn’t just a sin against the body of Christ. It’s also a sin against one’s own body:

Flee from sexual immorality. Every other sin a person commits is outside the body, but the sexually immoral person sins against his own body. Or do you not know that your body is a temple of the Holy Spirit within you, whom you have from God? You are not your own, for you were bought with a price. So glorify God in your body. (1 Corinthians 6:18–20)

For ones with the indwelling Holy Spirit to bring God into illicit acts is a terrible thing. Other sins, like stealing, also involve physical acts, but not in the intimate way sexual sin does. The Holy Spirit indwells Christians. The body is a temple for him, and Christians who commit sexual sin are dishonoring him. They owe God more. They’ve been bought with a price and owe him glory, not disdain. This aspect of sexual sin relates to Christians only. The lost aren’t part of the body of Christ and don’t have the indwelling Holy Spirit.

Another reason sexual immorality is a sin relates to all, both the lost and the saved. It’s because it dishonors the image of God in which we are made. It’s the same concept we saw regarding murder. Man is made in the image of God and anything that wrongly destroys that image or dishonors it is against God’s law.

Though I’ve implicitly used heterosexual sex to illustrate God’s moral law regarding immoral sexual activity, the same law applies for the same reasons to other forms of sexual immorality. Though the Bible specifically condemns various sexual perversions (Gen. 19:4-7; Lev. 18:22-23; Rom. 1:26-27; 1 Cor. 6:9-10) we don’t need those verses to know that they are against God’s moral law.

Those who argue that the Bible doesn’t condemn homosexual activity are wrong. It condemns it directly and indirectly, as sexual activity outside the bonds of marriage, which by God’s definition requires one man and one woman.

Any sexual activity outside of marriage is illicit. Sexual perversions are simply other ways to the same destructive ends we’ve already considered. We can succinctly state God’s moral law regarding non-marital sexual activity of any kind: It’s evil. Don’t do it.