Natural Law and Sexual Ethics

We live in a time of sexual “freedom.” It seems that anything—or almost anything—goes. Christian ethics regarding sexuality is seen as archaic, joy-killing, and harmful. What is most putrid to this sexualized culture is when someone attempts to use Bible verses to justify a sexual ethic or a vision of marriage. The Bible is dismissed as unauthoritative and irrelevant. Some people, well-meaning I’m sure, have taken the bait and seek to argue for sexual ethics in society and in marriage using natural law alone. That is, an argument based solely on a morality common to all and visible in the created order. However, this appeal to natural law, apart from divine revelation, becomes a wax nose that can be bent any which way.

In fact, in first century Corinth, people appealed to a kind of natural law to justify their sexual ethic quite contrary to a Christian worldview. There was a slogan in Corinth: “Food is meant for the stomach and the stomach for food” (1 Corinthians 6:13). The application of this natural law? If your belly craves food, then satisfy it. That’s what it’s made for. It’s only natural. But for the Corinthians, the application extended to sex as well. If your body craves sex, then satisfy it. Their appeal to natural law seems logical and is likely just as persuasive in our day as it was in theirs. The body has natural cravings for food and sex, and it is not wrong to satisfy it. That’s how the body works. It’s only natural. Therefore, the Corinthians were justifying sex with prostitutes as no big deal, just a natural bodily function!

How does Paul answer such an appeal to nature? He answers with Scripture. He quotes from Genesis and says, “For, as it is written, ‘The two will become one flesh’” (1 Corinthians 6:16). He goes on to explain that sex is not just physical but joins two bodies—and two spirits—together into one unity. There is a spiritual reality that transcends physical appearances. Sexual immorality is especially grievous for the Christian since “he who is joined to the Lord becomes one spirit with him” (1 Corinthians 6:17). So he asks, “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!” (1 Corinthians 6:15). What Paul is saying here is profound.

Like the spiritual connection we have in Christ through faith, sex joins two together into a spiritual union. What the Scriptures teach is that sex is much more than a physical craving that is to be satisfied. It has a unique and sacred purpose in God’s design of humanity.

Apart from Scripture and divine revelation, solely relying on “natural” law leaves us rudderless and prone to terrible consequences. I’m convinced that the pain, brokenness, disillusionment, depression, isolation, emptiness and hopelessness of those pursuing sexual “freedom” is because they are ignorant of—or rebellious to—God’s purpose and plan for sex and marriage. Without this knowledge from God people approach sex as a physical craving and run headlong into spiritual (and physical) ruin. The committed husband and wife who remained chaste before marriage and remain faithful to each other until the end have an infinitely better “sex life” than those who join themselves with countless others. I can say this, not just from collective human experience, but ultimately based on the authority of divine revelation.

In sum, we need a word from God to orient our lives—and every aspect of our lives. Thanks be to God that he has given us a book. We ignore it to our own peril. May we not be ashamed to employ God’s word, even in a world that thinks it irrelevant and unauthoritative. Throwing away our greatest weapon and restraining ourselves to use natural law in a sexualized age is foolhardy. “To the teaching and to the testimony! If they will not speak according to this word, it is because they have no dawn” (Isaiah 8:20).

Tim Stephens