At a glance, the seventh commandment seems right to almost everyone; literal adultery—extramarital sex—is generally frowned upon. But the law goes far deeper. It condemns “all unchastity.” God’s law governs everything about our sexuality. Understood that way, many people have no use for the seventh commandment. Unregulated sexual freedom is increasingly viewed as a human right.
But the seventh commandment is truly good for us. God knows—better than we do—how sex can build up or destroy. So he aims to guard us from the fallout of sexual sin and to promote safe, fruitful, enjoyable, God-honoring sexual relations.
How Does God View Sex?
The Bible applauds appropriate sex between a man and a woman married to each other. Biblical sex is not something to be ashamed of; the Song of Solomon overtly celebrates it! Scripture sets a pattern for God’s people to talk positively about sex from our pulpits and in private conversations.
God wired his people to “be fruitful and multiply and fill the earth” (Gen. 1:28). Before the fall, Adam and Eve enjoyed each other intimately with no shame (Gen. 2:24, 25), but sin tragically perverted and corrupted marital love.[i] It could not cancel the goodness of proper intimacy, however. After God confronted and comforted the first sinners, we read this: “Adam knew Eve his wife, and she conceived” (Gen. 4:1). Adam and Eve’s love-making and Eve’s conception signal to readers the hopefulness of God’s redeeming work. The rest of the Bible says that sex within marriage is a gift of our gracious God meant to promote companionship, prevent sexual sin, and populate the church and world with godly people.
But there is a darker side to sex. Sexual sin displeases God and degrades humans. God wills our sanctification—our becoming more and more perfect in knowledge, righteousness, and holiness. So God insists that we “abstain from sexual immorality” (1 Thess. 4:3). Sexual deviancy always deforms and detracts. It never satisfies. The sexual sin of believers is especially offensive; we sin against the body which God has bought with Jesus’s blood and in which God dwells by his Holy Spirit (1 Cor. 6:18–20). So throughout the Bible God warns against sexual immorality precisely because, being good, he truly wants the best for us.
And we must want the best for each other. The law’s second table tells us how we must love our neighbor. Unlawful sexual encounters with others—even when consensual—are always harmful and therefore unloving (Rom. 13:10). And sexual immorality is especially unloving to women; in a world where “might makes right,” women are always the biggest losers. It is often unrecognized that God’s code of sexual conduct—addressed first to men (Deut. 21:4)—protects women.
Because of the power of sex—for good or evil—God’s regulation of sexuality is ambitious and exacting, extending far beyond literal adultery. Biblically-sanctioned sex is always between a man and a woman married to each other; all sexual acts outside of marriage are sinful. And sexuality encompasses much more than the sex act; “all unchaste actions, looks, talk, thoughts, or desires” are sin (cf. Eph. 5:3, 4). Like all sin, sexual sin begins in the heart. This is why we must keep our hearts with all vigilance; from them flow the springs of life (Prov. 4:23). We are responsible for our thoughts and for how we feed them. We should learn to control ourselves in all areas; those generally undisciplined are hopelessly ill-prepared to “control [their] own bod[ies] in holiness and honor” (1 Thess. 4:4).
How Can I Steward My Sexuality?
Believers agree with the seventh commandment. But how do we practice it?
Hate sexual sin.
The dying-away of the old self requires “more and more to hate” sin (Q&A 89). God’s will for us in the seventh commandment is that we “detest [unchastity] wholeheartedly.” A casual sexual attitude invites the devil to entice and devour you. We should hate sexual sin even more than the devil hates us. Love for God demands hatred for sexual immorality.
Pornography is one of the most common and destructive sexual sins. Pornography use is adultery. “In some ways it’s worse than ‘ordinary’ adultery in that it involves multiple women, many of whom are nothing less than sexual slaves, forced to satisfy the adulterous desires of porn users.”[ii] Commit to never viewing anything that would incite you to “unchaste actions … thoughts, or desires.” And if you are trapped, get help.
Look out for your neighbor.
God forbids “whatever may incite someone to” unchastity. No one may blame another for his lust. Period. But no Christian should willingly lead another into sexual sin by how they dress or what they say. We must be careful not to awaken love before its time (Song 2:7, 8:4). We must also not awaken sexual interest in anyone to whom we are not married.
Make an escape plan.
Every temptation has a way out (1 Cor. 10:13). But we aren’t taking that truth seriously until we plan our escape. So “watch and pray that you may not enter into temptation” (Matt. 26:41). And don’t pray alone. Because sin flourishes in secret, become accountable to a trusted spiritual friend. Of course, accountability is no excuse for foolishness. We must avoid enticing situations and flee temptations immediately (Matt. 6:13).
Marriage is not for everyone (1 Cor. 7:7–8). And it doesn’t magically cure sin; single people uninterested in living “decent and chaste lives” won’t be helped by marriage. But those truly struggling to control their passions should work toward marriage (1 Cor. 7:2, 9). In 1 Corinthians 7, marriage answers Paul’s exhortation in chapter 6 to flee sexual immorality. Ulrich Zwingli was right: “There is nothing between chastity and marriage.”[iii]
Be sexually active in marriage.
“Decent and chaste” living within “the holy state of marriage” requires sexual activity (1 Cor. 7:3–5). Every spouse must “render conjugal duty, which is owing to each other. For, as the apostle argues [1 Cor. 7:4], in the married state neither person has power over his own body, but has delivered it into the power of the other.”[iv] Biblical marital sex can deepen married love and weaken adulterous inclinations.
Become more and more united to Christ
Our sexuality reveals our need for deep companionship. And our sexual brokenness proves our need for a Savior. Union with Christ is a marriage (Eph. 5:22–33). Jesus’s perfect faithfulness sanctifies us, satisfying our hearts’ desires. He rescues us from loneliness and selfishness. He gives us every reason to show our gratitude by loving and obeying him. Let’s believe and put into practice this commentary on the seventh commandment: “Let marriage be held in honor among all, and let the marriage bed be undefiled, for God will judge the sexually immoral and adulterous” (Heb. 13:4).