A Theology of Sex: Why Sexual Sin Matters

If sexual sins aren’t worse than any other sins, then why do we end up talking about them so much? It’s a fair question and one I’ve often thought. I mean America in particular has a real problem with the sin of gluttony, but rarely a sermon is preached against it. Perhaps it’s because churches like to have pot lucks after service and not orgies. But because the Bible talks about sex in some pretty important ways, and because sex has such a strong pull on humanity, there is reason to focus on it as often as we do.

Two particular passages come to mind when I think about the importance of talking about sexual sin. The first is found in 1 Corinthians 6:15-20. Here Paul is arguing against a heresy in the Corinthian church which taught some form of a proto-gnosticism. False teachers had said that what you do with the body is irrelevant to your spirituality. So you might not call it sin, but you can do what you want to. But such teachers were wrong, and Paul explains why. He writes:

¹⁵ 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!  ¹⁶ 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.”  ¹⁷ But he who is joined to the Lord becomes one spirit with him.  ¹⁸ Flee from sexual immorality. Every other sin a person commits is outside the body, but the sexually immoral person sins against his own body.  ¹⁹ 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,  ²⁰ for you were bought with a price. So glorify God in your body. 1 Corinthians 6:15-20

From Paul’s point of view the Christian’s body has been purchased by Christ and joined to Him. Therefore what you do with your body is a reflection on him. So Paul’s point about what you do with a prostitute is what Christ does with a prostitute. The implication for our sexual sins is obvious.

There is one peculiar phrase in this passage, though. Verse 18 states that sexual sin is the only sin a person commits against their own body, and the implication is that it is therefore more pernicious. The logic actually doesn’t seem to make sense to me at first glance. Wouldn’t it be more evil to do harm to another? Wouldn’t such sin fly in the face of the great principle of love your neighbor? What is Paul suggesting here? It’s not actually very clear. John MacArthur writes:

I believe he is saying that, although sexual sin is not necessarily the worst sin, it is the most unique in its character. It rises from within the body bent on personal gratification. It drives like no other impulse and when fulfilled affects the body like no other sin. It has a way of internally destroying a person that no other sin has. Because sexual intimacy is the deepest uniting of two persons, its misuse corrupts on the deepest human level. That is not a psychological analysis but a divinely revealed fact. Sexual immorality is far more destructive than alcohol, far more destructive than drugs, far more destructive than crime. (The MacArthur New Testament Commentary: 1 Corinthians, 151).

Regardless of how we infer what Paul might have meant, it’s clear to the apostle that sexual sin is a special category that deserves more serious thought.

The other passage to reflect on in this subject is found in Ephesians 5. In this common passage Paul is making a connection between a husband and wife relationship and the gospel. As husbands love their wives like Christ loves the church they are reflecting the gospel. There’s no plain statement here about sex, but certainly that falls under the vast umbrella of marital union. Our sex life is partially a reflection of Christ’s love for the church. The implication of Ephesians 5:25-32 is that what we do in sex can communicate either truth of falsehood about the gospel. In fact both passages seem to indicate this principle.

What makes sexual sin particularly awful is the manner in which it lies about Jesus’ love for his church. By committing sexual sin we are insinuating that this is what Christ’s love is like. It is like a one-night stand, it is like lust without emotional connection, it is like a voyeuristic self-pleasure, it is self-indulgent impulse, and so on and so on. We lie about the gospel by indulging in sexual sin and that’s what makes this so worth our time considering.

Sexual sin may get talked about a lot, but I fear that most often the conversation starts with discussions about moral behavioral change and not with the gospel. When we consider the real drastic implications of what we are saying when we engage in sexual sin it puts the focus on the right place. We lie about Jesus. So therefore it’s not just about modifying our behavior it’s about loving Christ, and that should be the right starting place for the behavioral change. Sexual sin matters because it is related to the gospel!