Evidence indicates that we Christians are about as infected with sexual immorality as the broader culture. So now more than ever, we need to hold fast to our Creator’s mandate that sex be reserved for marriage.

But we need to do more than just remind people of Bible verses prohibiting sex outside of marriage. We’ve done that for quite awhile and it obviously isn’t doing much good! We need to help people understand why sex is such a big deal to God. Here are three aspects of the Bible’s teaching on sex that may help us better appreciate why he cares so much about what we do with our bodies.

First, the Bible teaches that something profoundly sacred happens whenever two people engage in sexual intercourse. In the words of Jesus, the two people “are no longer two, but one.” Jesus goes on to add that “what God has joined together, no one should separate” (Matthew 19:5-6, emphasis added). God himself is involved in creating a new “one” out of the two! The triune God whose very being reflects a loving unity-in-plurality creates a new unity-in-plurality through the act of sexual intercourse. Nothing could be more sacred than that!

It’s important we understand that the Bible teaches us this “one flesh” reality is created whenever two people engage in sexual intercourse—even when it’s done “causally,” as when a man has sex with a prostitute (this is Paul’s point in I Corinthians 6:16). In sharp contrast to the prevailing attitude of our promiscuous culture, there clearly is no such thing as “causal sex” for God.

Second, intercourse is the sacred sign and seal of the marriage covenant. This is why in Scripture and in the Jewish tradition a couple wasn’t considered married until after they’d had intercourse. This is also why if a man had forced sex with a virgin, he was commanded to marry her in the Old Testament (Deuteronomy 22:28-29). Since he’d already sealed the marriage covenant, he now had an obligation to live up to the covenant.

This means that whenever two people engage in sexual intercourse, they are sealing a covenant that is designed to never be broken. And if either moves on to engage in sexual intercourse with another, they’re breaking the first covenant that they sealed, however unintentionally.

This could not be more serious, for the “one flesh” reality that God creates through intercourse and the marriage covenant it seals is foundational to society and to God’s purpose for the human race (Genesis 2:21-25, 1:27-28). This is undoubtedly why Paul treats sexual sin more severely than other types of sin (I Corinthians 6:13-20). It’s why he commands disciples to run in the opposite direction from sexual immorality, rather than see how close they can get without “crossing the line,” which is the thinking of many today (I Corinthians 6:18).

Third, the “one flesh” reality God creates through sexual intercourse is a sign and seal not only of the marriage covenant. It also is a symbol of the profound relationship Christ has with the Church. In I Corinthians, Paul draws a parallel between the “one flesh” reality God creates through intercourse (even with a prostitute!) with the “one spirit” relationship all believers have with Christ (I Corinthians 6:16-17). And in Ephesians, Paul says that the mystery of the “one flesh” reality God creates between a husband and wife reflects the “profound mystery” of the oneness of Christ and his Church (Ephesians 5:31-32). No other human activity is invested with such profound, sacred significance.

We honor the beauty and sacredness of Christ’s relationship with the Church and the incredible price he paid to enter into it when we honor the beauty and sacredness of its sign. When we honor the biblical teaching that sexual intercourse is to be enjoyed only by those who have paid the ultimate price by pledging their lives to each other “for better or for worse,” we honor the unique, priceless beauty of Christ’s relationship with the Church, to which sexual intercourse points as a sign.

On the other hand, when we treat sexual intercourse as something that anyone can enjoy whenever and with whomever they please, we dishonor the uniqueness and beauty of the reality to which sexual intercourse points.

So, why is sex such a big deal for God? Through sexual intercourse God himself creates a new unity-in-plurality that reflects his own being and that seals a covenant that is central to his plans for humanity and foundational to the well-being of society. And through sexual intercourse, to be enjoyed only by those who sacrifice everything for one another within the covenant of marriage, God symbolizes the beauty and costliness of his own mysterious relationship with the Church.

Sex is among the most sacred gifts God has given us, yet our culture treats it as having little more significance than a form of recreation. As kingdom people who are called to be “set apart” and “peculiar,” let’s honor God by holding fast to the beauty of this gift and resisting the ugliness of our promiscuous culture.

It is a big deal to God. It must remain a big deal to us.


Greg Boyd is the Senior Pastor of Woodland Hills Church in St. Paul and former professor of theology at Bethel University. He has published 15 books, including the best-selling and award-winning “Letters From a Skeptic” and most recently “The Myth of a Christian Nation.”