The Seventh Commandment: Thou Shalt Not Commit Adultery¶

A Plain-English Summary of the Biblical Evidence

The seventh commandment is two words in the original Hebrew: "Thou shalt not commit adultery." But its scope extends far beyond marital infidelity. This study traced the commandment from its creation foundation (Genesis 2:24), through the comprehensive sexual ethic of Leviticus 18, Jesus's extension to the heart level, Paul's body-temple theology, and the eschatological warnings of Revelation -- and drew its findings from what the text says.

The Creation Foundation¶

The seventh commandment does not begin at Sinai. It rests on a foundation laid at the very beginning of human history:

"Therefore shall a man leave his father and his mother, and shall cleave unto his wife: and they shall be one flesh." (Genesis 2:24)

This verse establishes the pattern: leave, cleave, one flesh. Marriage is a God-established institution, created before any nation or legal system existed. Jesus Himself appealed directly to this creation baseline when addressing questions about divorce:

"Have ye not read, that he which made them at the beginning made them male and female, And said, For this cause shall a man leave father and mother, and shall cleave to his wife: and they twain shall be one flesh? Wherefore they are no more twain, but one flesh. What therefore God hath joined together, let not man put asunder." (Matthew 19:4-6)

Jesus treats Genesis 2:24 as the governing standard for marriage. When challenged about the Mosaic provision for divorce, He responded:

"Moses because of the hardness of your hearts suffered you to put away your wives: but from the beginning it was not so." (Matthew 19:8)

The Mosaic divorce provision was a concession to human weakness, not the creation ideal. Jesus subordinated Moses to creation -- and creation's standard is permanence.

Known Before Sinai¶

The moral content of the seventh commandment was recognized long before Sinai by Israelites and non-Israelites alike. When Abimelech, a pagan king, unknowingly took Sarah, God warned him in a dream and called it "sinning against me" (Genesis 20:3, 6). A Philistine king recognized that adultery brings guilt upon a nation (Genesis 26:10-11). And Joseph, when tempted by Potiphar's wife, refused with these words:

"How then can I do this great wickedness, and sin against God?" (Genesis 39:9)

Joseph called adultery "great wickedness" and "sin against God" -- not because he had read the Ten Commandments (they had not yet been given), but because this moral truth was already known.

The Commandment Word¶

The Hebrew verb in the commandment is naaph, which specifically denotes violation of the marriage covenant -- sexual relations with another person's spouse. It is narrower than the broader Hebrew word zanah (fornication or harlotry). But the commandment's application extends well beyond the narrow definition of naaph.

"Thou shalt not commit adultery." (Exodus 20:14)

Leviticus 18: A Universal Sexual Ethic¶

Leviticus 18 expands the seventh commandment into a comprehensive code covering incest (thirteen specific relationships), adultery, homosexual acts ("Thou shalt not lie with mankind, as with womankind: it is abomination"), and bestiality. But the most important feature of this chapter is its conclusion:

"Defile not ye yourselves in any of these things: for in all these the nations are defiled which I cast out before you: And the land is defiled: therefore I do visit the iniquity thereof upon it, and the land itself vomiteth out her inhabitants." (Leviticus 18:24-25)

The Canaanites had no access to the Mosaic law, yet they were judged for these same violations. This establishes the sexual ethic as universal -- not a rule for Israel alone. The text further specifies that these prohibitions apply to "any of your own nation, nor any stranger that sojourneth among you" (Leviticus 18:26). The standard applies to everyone within the community, not just the ethnically Israelite.

Jesus Extended the Commandment to the Heart¶

In the Sermon on the Mount, Jesus quoted the seventh commandment and then extended it inward:

"Ye have heard that it was said by them of old time, Thou shalt not commit adultery: But I say unto you, That whosoever looketh on a woman to lust after her hath committed adultery with her already in his heart." (Matthew 5:27-28)

The Greek construction is precise: "for the purpose of lusting" -- this is not about an involuntary glance but the deliberate cultivation of sexual desire. Jesus places the point of guilt at the intent, not just the act. The heart is the battleground.

Jesus also identified the heart as the origin of all sexual sin:

"Out of the heart proceed evil thoughts, murders, adulteries, fornications." (Matthew 15:19)

Marriage, Divorce, and Remarriage¶

Jesus restricted the grounds for divorce to a single exception:

"Whosoever shall put away his wife, except it be for fornication, and shall marry another, committeth adultery." (Matthew 19:9)

Mark and Luke record the same teaching without the exception clause (Mark 10:11-12; Luke 16:18). Paul affirmed the permanence of the marriage bond:

"The woman which hath an husband is bound by the law to her husband so long as he liveth; but if the husband be dead, she is loosed from the law of her husband... if, while her husband liveth, she be married to another man, she shall be called an adulteress." (Romans 7:2-3)

Malachi framed divorce as a betrayal of the marriage covenant itself:

"The LORD hath been witness between thee and the wife of thy youth, against whom thou hast dealt treacherously: yet is she thy companion, and the wife of thy covenant... he hateth putting away." (Malachi 2:14, 16)

Paul's Body-Temple Theology¶

Paul provided the theological foundation for the commandment's continuing force in the New Testament era. The believer's body is not merely a physical container -- it is sacred space:

"Know ye not that your body is the temple of the Holy Ghost which is in you, which ye have of God, and ye are not your own? For ye are bought with a price: therefore glorify God in your body." (1 Corinthians 6:19-20)

Sexual union creates a one-flesh bond (Paul quotes Genesis 2:24 to make this point in 1 Corinthians 6:16), which means sexual immorality desecrates the temple of the Holy Spirit. Paul's command is emphatic:

"Flee fornication. Every sin that a man doeth is without the body; but he that committeth fornication sinneth against his own body." (1 Corinthians 6:18)

The word is "flee" -- not resist, not negotiate, but run. The theology behind the command is divine ownership: believers do not belong to themselves. They have been purchased, and their bodies are to glorify God.

Paul quoted the seventh commandment as the first among the Decalogue commands summarized in love:

"Thou shalt not commit adultery, Thou shalt not kill, Thou shalt not steal... it is briefly comprehended in this saying, namely, Thou shalt love thy neighbour as thyself." (Romans 13:9)

The Created Order¶

Paul addressed homosexual acts as departures from the created order:

"For even their women did change the natural use into that which is against nature: And likewise also the men, leaving the natural use of the woman, burned in their lust one toward another; men with men working that which is unseemly." (Romans 1:26-27)

The language of "natural use" and "against nature" invokes the creation standard. The compound Greek word arsenokoitai (used in 1 Corinthians 6:9 and 1 Timothy 1:10) is formed from the Greek words for "male" and "bed," directly echoing the vocabulary of the Levitical prohibitions. The Old Testament calls these acts "abomination" (Leviticus 18:22; 20:13); Paul calls them contrary to the natural order established at creation.

Hebrews 13:4 -- The Clearest Single-Verse Summary¶

One verse in Hebrews captures both the positive and negative dimensions of the commandment in a single sentence:

"Marriage is honourable in all, and the bed undefiled: but whoremongers and adulterers God will judge." (Hebrews 13:4)

The marriage bed is affirmed as honorable and pure. But those who violate it -- both the broader category of the sexually immoral and the specific category of adulterers -- will face divine judgment. The verb "will judge" is in the future tense, pointing to certain, inescapable accountability.

The Consequences Are Eternal¶

Multiple New Testament authors state that unrepentant sexual immorality excludes from God's kingdom:

"Neither fornicators, nor idolaters, nor adulterers, nor effeminate, nor abusers of themselves with mankind... shall inherit the kingdom of God." (1 Corinthians 6:9-10)

"Whoremongers... shall have their part in the lake which burneth with fire and brimstone: which is the second death." (Revelation 21:8)

"Without are dogs, and sorcerers, and whoremongers, and murderers, and idolaters." (Revelation 22:15)

The sexually immoral are permanently excluded from the new creation.

But Grace Is Available¶

The gravity of sexual sin is matched by the possibility of transformation. Immediately after listing the sins that exclude from the kingdom -- including fornication, adultery, and homosexual practice -- Paul writes:

"And such were some of you: but ye are washed, but ye are sanctified, but ye are justified in the name of the Lord Jesus, and by the Spirit of our God." (1 Corinthians 6:11)

"Such were some of you" -- past tense. The Corinthian believers had been fornicators, adulterers, and practitioners of homosexual acts. But they had been washed, sanctified, and justified. Jesus told the woman caught in adultery: "Neither do I condemn thee: go, and sin no more" (John 8:11). The eschatological exclusion applies to those who do not repent. For those who do, grace is sufficient.

What the Bible Does NOT Say¶

The text does not specify the precise scope of the Greek word porneia (sexual immorality) in the divorce exception clause of Matthew 19:9 -- whether it refers to pre-marital sin, adultery, or a broader category.
The text does not explicitly state whether the "not under bondage" clause of 1 Corinthians 7:15 permits remarriage after abandonment by an unbelieving spouse, or only releases from the obligation to maintain the marriage.
The text does not address sexual orientation as a modern category. It addresses sexual acts and desires.
The text does not say that adultery is the unforgivable sin. Multiple passages affirm that repentance and transformation are possible.

Conclusion¶

The seventh commandment protects the one-flesh marriage union that God established at creation. Its moral content was recognized before Sinai by Israelites and non-Israelites alike. Leviticus 18 expanded its scope to a comprehensive sexual ethic and established that ethic as universal by judging the Canaanites for the same violations. Jesus extended the commandment from the outward act to the inward disposition, making lustful intent equivalent to adultery in the heart, and restricted divorce to the ground of sexual immorality while appealing to the creation standard as the governing norm. Paul grounded sexual purity in the theology of the body as the temple of the Holy Spirit, quoted the commandment as part of the law that love fulfills, and identified homosexual acts as departures from the created order. Hebrews affirms the marriage bed and declares judgment on those who defile it. Revelation excludes the sexually immoral from the new creation.

From Genesis to Revelation, from creation to the new earth, no biblical author departs from this trajectory. The commandment addresses both act and intent, applies universally, and carries consequences that extend into eternity -- yet repentance and transformation remain available through grace.

Based on the full technical study completed 2026-02-27

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