The Grammar of Holiness: Boundaries for a People Set Apart Text: Leviticus 18:19-23
Introduction: The Land Vomits
We live in a time that prides itself on having no boundaries, particularly when it comes to sexual expression. Our culture treats sexual desire as the central, defining attribute of personhood, and any attempt to regulate it, to channel it, or to forbid certain expressions of it, is considered the highest form of bigotry and oppression. The modern world wants a sexual ethic that amounts to little more than enthusiastic consent between adults. But this is a recipe for cultural suicide, and the Scriptures tell us why.
The book of Leviticus, and this chapter in particular, is God's foundational instruction on holiness. Holiness is not a mystical feeling or a pious sentiment. Holiness means being "set apart." It means being different. Israel was called to be holy because God is holy, and they were to be set apart from the nations around them, specifically Egypt, where they had come from, and Canaan, where they were going. And the central marker of the paganism of Egypt and Canaan was their sexual ethics, or rather, their lack of them. Their worship and their daily lives were saturated with sexual confusion, perversion, and violence.
God's laws in this chapter are not arbitrary restrictions designed to make life miserable. They are boundary markers. They are the protective walls around the garden of human sexuality, designed to make it fruitful, beautiful, and safe. When a people group begins to tear down these walls, they do not find liberation. They find ruin. God warns Israel that the Canaanites practiced all these abominations, and the result was that "the land became unclean, so that I punished its iniquity, and the land vomited out its inhabitants" (Lev. 18:25). This is a startling personification. The very ground, the created order itself, has a gag reflex to certain kinds of human behavior. Creation is not neutral. It is designed and built with a moral grain, and when you go against that grain, you get splinters. When a whole culture goes against that grain, the land itself expels them.
This is a sober warning for our own time. We are busily and gleefully committing the very sins that caused the land of Canaan to vomit. We have legalized them, we celebrate them, we teach them to our children, and we persecute those who object. We should not be surprised when the land starts to heave. The laws in our text today are not just for ancient Israel. They reveal the permanent, created structure of God's world. They are the grammar of holiness, and to violate them is to speak cosmic nonsense, which always ends in judgment.
The Text
‘Also you shall not approach a woman to uncover her nakedness during her menstrual impurity. And you shall not lie sexually with your neighbor’s wife, to be defiled with her. And you shall not give any of your seed to pass them over to Molech, nor shall you profane the name of your God; I am Yahweh. And you shall not lie with a male as one lies with a female; it is an abomination. Also you shall not lie with any animal to be defiled with it, nor shall any woman stand before an animal to mate with it; it is a perversion.
(Leviticus 18:19-23 LSB)
Holiness in the Marital Bed (v. 19)
The first prohibition deals with an internal regulation of the marriage bed.
"‘Also you shall not approach a woman to uncover her nakedness during her menstrual impurity." (Leviticus 18:19)
Now, on the surface, this appears to be a purely ceremonial law, tied to the Old Covenant's purity codes. And in one sense, it is. The issue of blood in the Old Testament was a picture of death, a reminder of the curse. Contact with it rendered one ceremonially unclean. But we must not dismiss it so quickly. The moral law is often illustrated and buttressed by the ceremonial. What is the underlying principle here?
This law teaches restraint, honor, and reverence for the life-giving capacity of a woman's body. The world says that if it feels good, you have a right to it, whenever you want it. God says that even within the covenant of marriage, there are times for restraint. This is not because the woman is dirty or because the act is shameful, but because it is holy. The processes of life and death are not to be treated casually. This law elevates the marriage bed from a place of mere animal appetite to a place of covenantal honor. The husband is taught to honor his wife's body and its rhythms, and the couple is taught that their union is about more than just personal gratification. It is tied to the great themes of life and death, which belong to God. In the New Covenant, the ceremonial aspect has passed away in Christ, but the principle of honoring one another's bodies remains (1 Cor. 7:4-5).
The Sanctity of the Covenant (v. 20)
Next, the law moves from the internal boundary of marriage to its external boundary.
"And you shall not lie sexually with your neighbor’s wife, to be defiled with her." (Leviticus 18:20)
This is the prohibition against adultery, the seventh commandment. Adultery is not just a private mistake. It is a violation of a covenant, an act of theft, and a profound injustice. Notice the wording: "your neighbor's wife." It is a sin against your neighbor. You are stealing what is most precious to him, destroying the one-flesh union that God created to be a picture of Christ and the Church. You are sowing chaos, confusion, and heartbreak into the fundamental building block of society.
The text says this act "defiles" you. Sin is not just breaking a rule; it is polluting yourself. It stains the soul. Adultery is a particularly defiling sin because it is a lie enacted with the body. It takes the act God designed for covenantal unity and turns it into an instrument of betrayal and division. This is why the book of Proverbs warns so starkly that the adulterer "destroys his own soul" (Prov. 6:32). Our society has trivialized adultery, treating it as a common plot point in sitcoms. But God says it is a defilement that strikes at the heart of social order. A society that is casual about adultery will not long be a society at all.
The Horror of Idolatry (v. 21)
The logic of the text then makes a startling but profound leap from sexual sin to idolatry.
"And you shall not give any of your seed to pass them over to Molech, nor shall you profane the name of your God; I am Yahweh." (Leviticus 18:21)
This is not a random interruption. The Holy Spirit is teaching us that disordered worship and disordered sexuality are two sides of the same coin. When you abandon the true God, you will inevitably abandon His sexual ethic. Molech was a Canaanite deity to whom people would sacrifice their children, passing them through the fire. This is the ultimate expression of paganism. Instead of receiving children as a gift from God, you sacrifice your children to your god to get what you want, whether that be a good harvest or a better career.
And let us not be mistaken. We are a Molech-worshipping culture. We do not use bronze statues, but we have clean, sterile clinics. We sacrifice our children by the millions on the altar of convenience, career, and sexual freedom. The logic is identical: the child is an obstacle to my self-fulfillment, so the child must be eliminated. This is a direct profaning of the name of God. God is the author of life. To take innocent life, particularly the life of your own child, is to spit in the face of the Creator and declare that you are god, you are the one who decides who lives and who dies. The text concludes with the ultimate reason: "I am Yahweh." He is the self-existent, covenant-keeping God. He defines reality. His name must not be profaned.
The Grammar of Creation (v. 22-23)
The final two verses address sins that are a direct assault on the created order itself.
"And you shall not lie with a male as one lies with a female; it is an abomination. Also you shall not lie with any animal to be defiled with it, nor shall any woman stand before an animal to mate with it; it is a perversion." (Leviticus 18:22-23)
Here we have the clear prohibition of homosexuality and bestiality. The language is strong. Homosexual acts are called an "abomination," and bestiality is called a "perversion." An abomination is something that is utterly repugnant to God's holiness. A perversion is a twisting, a turning of something from its created purpose.
The sin here is not a lack of love or commitment, as our modern apologists would have it. The sin is the act itself, because it is a rebellion against the design of the Creator. God made humanity male and female (Gen. 1:27). This binary is not a social construct; it is a biological and theological reality. The one-flesh union of a man and a woman is the icon of the gospel, the picture of Christ and His bride, the Church (Eph. 5:32). Homosexual acts are a direct contradiction of this created grammar. It is an attempt to join together what God has made distinct in a way He never intended. It is trying to spell a word with the wrong letters. The result is not just a mistake; it is cosmic nonsense.
Bestiality is a further step into this chaos. It is the erasure of the boundary between man and beast. Man was made in the image of God, given dominion over the animals. To engage in sexual acts with an animal is a profound degradation of that image. It is an abdication of man's created place and a descent into utter confusion. Both of these acts are the logical end of a worldview that rejects the Creator. If there is no designer, there is no design. If there is no design, there are no boundaries. All that is left is appetite.
Conclusion: The Gospel and the Land
These are hard words for modern ears. They are offensive. But they are the words of a holy God who loves us enough to tell us the truth. The central problem with all these sins, from adultery to child sacrifice to homosexuality, is that they profane the name of God. They misrepresent His character and His creation. They are a form of blasphemy.
The temptation for the modern church is to be embarrassed by these texts, to apologize for them, or to explain them away. But that is to abandon the gospel. The good news is not that God has lowered His standards to meet ours. The good news is that Christ died for sinners, for those who have committed these very abominations. Paul, after listing a similar catalog of sins, including adultery and homosexuality, says to the Corinthian church, "And such were some of you. But you were washed, you were sanctified, you were justified in the name of the Lord Jesus Christ and by the Spirit of our God" (1 Cor. 6:11).
There is no sin so defiling that the blood of Christ cannot cleanse it. There is no perversion so twisted that the grace of God cannot straighten it. The call of the gospel is a call to repentance, a call to turn away from the path that leads to the land vomiting, and to turn toward the God who created the land. It is a call to submit our sexuality, our families, our worship, and our entire lives to the lordship of Jesus Christ. He is the one who makes us holy. He is the one who keeps the land, and His people, from being defiled. And He alone is our hope.