When Sex Becomes Sin

“How can anything so good be so bad?” If sex is as good as we portrayed it in the previous chapter, why is it that many sexual acts are condemned in Scripture? The answer is that like most good things, sex was created to exist within prescribed boundaries. As long as it stays within those boundaries, it is good. The moment it moves outside them, it becomes bad.

Take water and fire as examples. Water is a great gift of God. Without it we would die. Yet when water is out of control, when it violates its proper boundaries, it can wreak terrible destruction—as anyone knows who has seen a flood or a tidal wave. Fire is likewise a great gift of God, but when out of control it can destroy a house, decimate a forest, and inflict painful and horrible death.

The best gifts of God are powerful, and when out of control that power becomes ruinous. So it is with sex. Sex outside marriage is so bad precisely because sex inside marriage is so good.

God’s Will Is Not Lost

Many of us spend great energy, time, and money trying to “find God’s will” (with the implication that it’s somehow lost or obscure). But there’s no mystery about God’s will in most matters of sexual behavior:

It is God’s will that you should be holy; that you should avoid sexual immorality; that each of you should learn to control his own body in a way that is holy and honorable, not in passionate lust like the heathen, who do not know God; and that in this matter no one should wrong his brother or take advantage of him. The Lord will punish men for all such sins, as we have already told you and warned you. For God did not call us to be impure, but to live a holy life. Therefore, he who rejects this instruction does not reject man but God, who gives you his Holy Spirit (1 Thessalonians 4:3-8).

The apostle Paul considers our personal holiness inseparable from our sexual behavior. There is no holiness where there is immorality. Like oil and water, the two do not mix. If we violate God’s sexual standards, no matter what else we do or don’t do, we simply cannot be in God’s will. We need to pray for power to accomplish His will in sexual matters but not to find out what that will is. Scripture makes it clear.

The Moral Climate of Biblical Times

The biblical standards of sexual morality stood in stark contrast to the accepted social norms of most of the ancient cultures. The people of Israel were surrounded by heathen nations characterized not only by pagan worship but the grossest forms of immorality. Canaanite religions featured the worship of phallic fertility gods and multi-breasted goddesses, and their rituals often included lewd dances followed by sexual intercourse and full-scale orgies. Prostitutes, both male and female, were a central part of the temple worship.

While the societies in the New Testament era were generally more civilized than the Canaanites, their sexual mores were just as bad. The Greek writings of Plato, Lucian, and many others elevated homosexuality. Immorality was a way of life in Greek cities like ancient Corinth, where a thousand prostitutes, priestesses of Aphrodite, walked the streets and gave their fees to the temple priests. In time, the city’s name was coined in a verb form (corinthiazomai) that actually meant to have intercourse with a prostitute.

The Christians in New Testament Corinth lived in a new city built a hundred years after ancient Corinth was destroyed. Nevertheless, the same spirit of immorality prevailed, still rooted in the mingling of pagan religion and immorality (2 Corinthians 6:15-20). No wonder the Corinthian Christians, raised in this environment had such struggles with sexual temptation.

Taking their cue from the rampant immorality of the Greek culture they assimilated, Roman emperors set a national example of notorious immorality. The emperor Caligula lived in incest with his sister, as did Nero with his own mother. Nero also married a young man. Julius Caesar was likewise a known homosexual, and the emperor Hadrian was extremely promiscuous with men and women alike.

Promiscuity was the norm, fidelity was a foreign concept. But the fledgling Christian faith did not surrender to the secular drift, insisting that those who named the name of Christ live in sexual purity: “Chastity was the one completely new virtue which Christianity introduced into the pagan world.”1 It was a distinction so basic, so fundamental, that the absence of purity would nullify the credibility of the Gospel. No wonder it is repeatedly stressed in the New Testament epistles.

But among you there must not be even a hint of sexual immorality, or of any kind of impurity, or of greed, because these are improper for God’s holy people. Nor should there be obscenity, foolish talk or coarse joking, which are out of place, but rather thanksgiving. For of this you can be sure: No immoral, impure or greedy person—such a man is an idolater—has any inheritance in the kingdom of Christ and of God. Let no one deceive you with empty words, for because of such things God’s wrath comes on those who are disobedient. Therefore do not be partners with them (Ephesians 5:3-7).

Other passages specifically state that those living in sexual immorality will not inherit the kingdom of God (I Corinthians 6:9-10; Revelation 22:14-15). These verses are hard to reconcile with the grim reality of sexual sin among Christians. Even if we do not know what to make of them, however, they demonstrate how much God hates sexual sin. They also show the basic incompatibility of the new life in Christ and the life of immorality. Simply put, Scripture leaves no place for sexual impurity in the Christian life, Christian family, or Christian Church.

The Purity PrincipleA Closer Look at Scripture’s View of Immorality

Scripture uses many terms for sexual immorality. Some of these are close synonyms, and many have overlapping meanings. To summarize, under Old Testament law there were four readily identifiable major categories of sexual sin:

1. Fornication: any sexual relations outside of marriage, including those between two unmarried people.

2. Adultery: sexual relations with someone other than one’s spouse or with the spouse of another.

3. Homosexuality: sexual relations between two people of the same gender—males with males or females with females.

4. Bestiality: sexual relations with an animal.

Other sexual crimes are specifically addressed but fall under one or more of these categories. Rape and incest, for instance, are particularly despicable brands of fornication that might also be adultery or homosexuality, depending on who is involved.

Still other sexual sins are dealt with not in precept, but in principle. When Ham looked upon the nakedness of his father Noah and told his brothers, they walked into Noah’s tent backwards to cover him, being careful not to look (Genesis 9:20-27). While commentators disagree on precisely what Ham was guilty of, Noah’s severe reaction makes clear that his actions or attitude were highly inappropriate. Presumably, choosing to look at and tell others of his father’s nakedness demonstrated a disrespect for his sexual sanctity and privacy. This principle has application both to those who display their nudity to others and those who delight in gazing at the nudity of others.

Lust: The Battle in Your Mind

The sex drive is powerful. Many say it is just another urge, like hunger and thirst, and sexual intercourse just another biological function. Animals eat, drink, sleep, excrete, and copulate, and people are animals, so…

But Paul tells the Corinthians something different:

Food was meant for the stomach and the stomach for food; but God has no permanent purpose for either. But you cannot say that our physical body was made for sexual promiscuity; it was made for the Lord, and in the Lord is the answer to its needs (1 Corinthians 6:13, Phillips).

Paul insists that the analogy between satisfying our hunger for food and indulging our sexual desires is invalid. “Natural” does not always mean “right.” While other urges exist for our physical maintenance, sex does not. We will die without food and water. We will not die without sex. Sex is never an emergency, immorality never a necessity. Lust, however, tells us otherwise.

What Does Scripture Say About Lust?

Sexual lust is condemned in the Old Testament. As we briefly noted in the previous chapter, the Tenth Commandment prohibits the coveting of another person’s marriage partner (Exodus 20:17). In vivid detail Proverbs repeatedly warns against the lust toward immorality, saying it is the fool who gives in to lust and the wise who resists it (Proverbs 2:16-19; 5:1-23; 6:23-29).

We can learn a great deal about lust through the examples, primarily negative, of Samson and Delilah, David and Bathsheba, and Hosea and Gomer. The prophets’ picture of Israel as God’s unfaithful wife also portrays the ugliness of lust and immorality (Jeremiah 3, Ezekiel 16).

But the key to the entire biblical teaching on lust is found in Jesus’ Sermon on the Mount:

“You have heard that it was said, ‘Do not commit adultery.’ But I tell you that anyone who looks at a woman lustfully has already committed adultery with her in his heart” (Matthew 5:27-28).

Jesus cuts to the moral root of the command. He recognizes that morality resides first in the heart or the mind. Pharisees emphasized the eternal, as if one could live up to God’s standards just by refraining from a physical act. Jesus raised the moral bar, saying that lust is not only the source of sexual sin, but is itself sin. He closed the door to the notion of the Pharisees that a man could undress a woman in his mind and remain pure. Lust is not the initial temptation toward sin, but is mentally succumbing to that temptation. We are to call upon our resources in Christ and be transformed by the renewing of our minds (Romans 12:2). We are to deny and put to death lust when it tries to get a grip on us (Colossians 3:5). We’re to fill our minds with what is pure (Philippians 4:8).

Lust is the counterfeit of love. Satan wants nothing more than that we should fail to see the difference between the two. At its root, lust is absolutely selfish; it uses another to gratify itself. Love, on the contrary, always acts in the best interests of the other person. “Love can always wait to give—lust can never wait to get.”

Sexual Temptation bookletSexual Sin Is Never “Out of the Blue”

Doug was a seminary student preparing for the ministry. One night he had an argument with his wife. Upset, he left home, drove to a nearby restaurant and tried to think things through over a cup of coffee. Soon Doug was engrossed in conversation with a young woman in the next booth. A few hours later, he was in bed with her.

Doug came to me ashamed and distressed. “How can I tell my wife? Will she ever forgive me?” he asked. “It was so sudden—there was no warning. Why did God let this happen?”

Mike is a successful executive, church leader, and family man. One day he met an attractive woman in an elevator and thought she was flirting with him. Before he knew it, Mike asked her to come into his office and undress in front of him. Fortunately, she refused. But Mike was shocked at what he had done (and might have done had she complied). “What is happening to me?” he asked. “How could I do something like this?”

From appearances, it seemed that Doug and Mike fell into sexual sin suddenly, without warning. But that was not the case.

Doug had worked nonstop to put himself through seminary. He came to subtly resent Joan, his wife, seeing her and the children as obstacles to his goal of graduating and entering the ministry. It had been two years since he had spent any meaningful time alone with Joan or communicated on other than a superficial level. Their relationship was stale, but both lacked the time or energy to change it.

When Joan and the children were visiting relatives, Doug took an evening break from his theology paper to get some fresh air. He ended up at an X-rated movie. Afterwards, every time he had sex with Joan he pretended she was a woman from the movie. He felt guilty, yet it didn’t appear to do any real harm.

What happened to Mike actually began years before he asked that girl to undress in his office. He had a problem with lust. Far worse, he failed to recognize or deal with that problem. On his lunch hour Mike often stopped by a convenience store to buy a paper or pack of gum. Invariably he wandered to the magazine rack and paged through Hustler or Penthouse. He never intended to (so he told himself). But he always did.

The same mind that wanted to serve Christ permitted itself to indulge in lustful fantasies. One day Mike’s mind, programmed by the immoral images he had fed it, prompted him to immoral action.

Sexual sin never comes out of the blue. It is the predictable result of a long natural process in which a mind susceptible to sin is granted unguarded exposure to immoral input.

It’s All in Your Mind

“Sow a thought, reap an action; sow an action, reap a habit; sow a habit, reap a character; sow a character, reap a destiny.”

We are what we think. Today’s thoughts are the stuff of which tomorrow’s character is made. Temptation may come suddenly, but sin does not. Neither does moral and spiritual fiber. It is the result of a process—a process over which we do have control. The best way to guard against tomorrow’s sexual temptations is to cultivate a pure mind today, a mind saturated not in the world’s input but in God’s.

Our sexual morality is the sum of a continuous series of choices, decisions, and actions, including all those tiny indulgences and minuscule compromises. Like a photographic plate accumulating light to form an image, our mind is the cumulative result of all we expose it to—whether godly or ungodly.

Male or female, young or old, Christian or non-Christian, all of us face a battle for sexual purity. The enemy is lust, the stakes are high, the reward is the peace and pleasure of purity.

And the battle is in our minds.

For more information on this subject, see Randy Alcorn's books The Purity Principle and Sexual Temptation: Establishing Guardrails and Winning the Battle.

Photo by Miroslav Kuruc on Unsplash

Randy Alcorn (@randyalcorn) is the author of over sixty books and the founder and director of Eternal Perspective Ministries