Leviticus 18


I explained last week that we’re in that part of the book of Leviticus which is known as the Laws of Holiness, because this part of the book contains laws and instructions to teach the people of Israel how they were to live as God’s people. Last week we looked at chapter 17 which contained laws forbidding idolatry and the eating of blood. Today, we come to chapter 18 which is mostly about unlawful sexual relations. It can be divided into four main sections: verses 1 to 5 contain an opening exhortation; verses 6 to 18 contain the list of unlawful sexual relations they were to avoid; verses 19 to 23 contains laws about other customs they were to avoid; and verses 24 to 30 contain warnings about the consequences of disobeying these laws.

Verses 1 to 5

Let’s turn to verses 1 to 5 and the opening exhortation. From verse 1 we see again that these laws came from the Lord to Moses. So, these are not laws which Moses devised on his own; these laws were given to him by the Lord. And the laws God gave to Moses were for the people of Israel. Many of the instructions we read in the earlier part of Leviticus were for the priests and concerned their special priestly duties. The laws in this chapter are for everyone.

And notice how the Lord introduces the laws. He said:

I am the LORD your God.

He’s saying to them that the reason they’re to pay attention to these laws and the reason they’re to obey them is because he’s the Lord their God. That’s the name the Lord used when he revealed himself to Moses at the burning bush, when he revealed his plans to deliver the Israelites from their captivity; and by using his name here in this chapter, he’s reminding the Israelites that he’s their God and the one who saved them from their captivity in Egypt. Therefore, since he’s their God, and their Saviour, they ought to obey him now. And that’s our motive for obeying the Lord as well: since he’s our God who has redeemed us by his Son, we ought to obey him to demonstrate our gratitude for all that he has done for us.

And then the Lord forbade the Israelites from doing what the Egyptians did; and he forbade them from doing what the Canaanites do. So, you once lived in Egypt and you saw how they lived; well, don’t do what they did. And I’m bringing you to Canaan and you’ll see how they live; well, don’t do what they do. Instead of being conformed to the ways of the Egyptians; and instead of being conformed to the ways of the Canaanites; be conform to my ways: obey my laws and be careful to follow my decrees.

What did the Egyptians and Canaanites do? Well, one commentator says they were ‘notorious for indiscriminate promiscuity’ and they did everything the Lord forbids in this chapter: they were incestuous; homosexuality was accepted; there was even bestiality. The pagans nations did whatever they liked, but God’s people were to be different; they were to follow, not their own sinful desires, but they were to follow God’s laws.

And in verse 5 God commanded his people to keep his decrees and laws, because the man and woman who obeys them will live by them. Well, Paul quotes this verse on two occasions in the New Testament. We’ll come back to this later, but for now let me say that in the context of this chapter God was promising his people long life in the Promised Land if they obey his laws. As God says later in verse 28, if they defile the Promised Land by disobeying his laws about unlawful sexual relations, the land will vomit them out of the land. In other words, if they disobey, they will be taken from the land. But if they obey the Lord, and do his will, then they will be allowed to remain in the land and to prosper there.

Verses 6 to 18

Lets turn to verses 6 to 18 to see what the Lord said about unlawful sexual relations. Verse 6 contains an opening principle:

No one is to approach any close relative to have sexual relations I am the Lord.

Why might this have been a temptation? We need to remember that the people of Israel were divided into tribes and clans; and most people married within their own clan in order to protect their inheritance of the land. And so, in that situation, it would have been too easy for someone to marry too close a relative. Hence the need for this basic principle:

No one is to approach any close relative to have sexual relations. I am the Lord.

In the following verses, this basic principle is unfolded in more detail. And so, the people were forbidden from having sexual relations with: their mother (v. 7); their step-mother (v. 8); their sister (v. 9); their grand-children (v. 10); their half-sister (v. 11); their aunt (vv. 12 and 13); the wife of their uncle (v. 14); their daughter-in-law (v. 15); their sister-in-law (v. 16). Furthermore they must not have sexual relations with both a woman and her daughter (v. 17). And they must not have sexual relations with the sister of their wife (v. 18).

Oddly, the chapter doesn’t mention the relationship between a man and his daughter, but it was obviously covered by the opening principle in verse 6.

Verses 19 to 23

Verses 19 to 23 contains laws about other customs they were to avoid. And so, verse 19: they weren’t to have sexual relations with a woman when she was menstruating, because she was ritually unclean. Verse 20: Adultery was forbidden. Verse 21: Don’t offer any of your children to the false god, Molech. Some of the commentators think this is an odd place to have this law, since all the others laws are about sexual relations, not idolatry. Some therefore suggest the law is placed here because the children were offered to Molech to be temple prostitutes. However, there’s historical evidence that children were offered to Molech as child sacrifices. In that case, this law might be placed here because killing your children in this way — though regarded by the pagans as acceptable — was regarded by the Lord their God as a wholly unacceptable way to treat the fruit of lawful sexual relations. Verse 22: homosexuality was forbidden. And verse 23: bestiality was forbidden.

The Egyptians may have done these things; the Canaanites may have done these things; but the Lord’s people were not to do these things.

Verses 24 to 30

And the chapter ends with warnings. The Lord said to his people that they must not defile themselves in any of these ways, because this is what the Canaanites used to do; and the reason the Lord was going to drive the Canaanites from the Promised Land and give it to the Israelites was because of the ways the pagan nations had defiled themselves. Even the land was defiled — says the Lord in verse 25 — because of what the pagan nations did; and so, the land vomited them out. It was as if the land was sick because of what they did in the land; and just as we might vomit when we’ve eaten something bad, so the land vomited the pagan nations out of the land, because the land was sickened by what they did.

That’s what happened to the pagan nations. But you — says the Lord in verse 26 — must be different and you must keep my decrees and my laws and you must not do any of these detestable things. If you defile the land — the Lord warns in verse 28 — it will vomit you out as it vomited the pagans nations out. And so, there’s the warning: don’t do what the nations do, because if you do, what happened to them will happen to you. Meanwhile, if anyone does do any of these things, that person must be cut off from the people. I mentioned before that it’s not clear what cutting off someone meant: it may mean they must be killed; it may mean God will cause them to die prematurely; it may mean they will be excommunicated from the people. Whatever it was, it was an act of discipline to preserve the purity of the people. Instead of tolerating sin in their midst, they were to act immediately to remove it from among them.


There are several points to make in conclusion. Firstly, we need to remember how the Old Testament law can be divided into three categories. There are the ceremonial laws about the sacrifices they were to offer and the rituals they were to keep; all of these have been fulfilled by Christ. Then there are the civil laws which were for the people of Israel as a nation which we are no longer obligated to keep unless they contain a principle which is still binding on us. And then there are the moral laws summarised by the Ten Commandments which all people everywhere are obligated to keep. And laws about sexual relations are part of God’s moral law which we must still keep today. So, while we don’t have to keep the laws about sacrifices which we find in the book of Leviticus, we still have to keep the laws about unlawful sexual relations.

Secondly, let’s go back to verse 5 and the words:

the man who obeys them will live by them.

Paul quotes those words in Galatians 3 and Romans 10 to contrast two ways to receive eternal life. One way is to say that the way to have life with God is by doing, or by keeping, the law:

Do this and you will live with God for ever.

Think of the rich young ruler who asked the Lord what he must do to inherit eternal life. But that way is a dead end, because no one is able to keep the law and to do all that God has commanded. Some of us break the law a lot; some of us break the law a little; but all of us have broken God’s law and all of us have sinned and fallen short of God’s glory. The law says:

Do this and you will live.

But we can’t. However, there’s another way and it’s the way of faith. The way of faith says:

Believe and you will live.

Believe in the Lord Jesus Christ — who has done all that the law requires and who has paid for our sins by his death on the cross, believe in him and you will have eternal life. So, when we read God’s moral law — when we read all of the laws in the Bible about sexual sins and about other sins — we know that we’re lawbreakers and we break God’s law in thought and word and deed in countless different ways. The law says ‘Do this and you will live’; but we know we haven’t done what the law says. But the good news is that Jesus Christ our Saviour has kept God’s law perfectly on our behalf. He’s done everything we were meant to do. And he died to pay for our sins. And by believing in him, we’re pardoned for what we’ve done wrong; and even though we may have done everything wrong, God treats us as if we’ve done everything right for the sake of Christ who did it all for us.

And for my final point, I want to quote from our church’s Confession which says:

11.5. God does continue to forgive the sins of those that are justified: and although they can never fall from the state of justification, yet they may by their sins fall under God’s fatherly displeasure, and not have the light of his countenance restored unto them, until they humble themselves, confess their sins, beg pardon, and renew their faith and repentance.

At the end of Leviticus 18, the Lord warned the Israelites about how they would fall under his displeasure and be removed from the land if they disobeyed him. And the reason he warned them was so that they would be careful to obey him. And we too must obey our Heavenly Father, because if we sin against him — without confessing our sin and seeking his forgiveness — it’s possible that we too will fall under his fatherly displeasure and be disciplined by him for what we have done wrong. Now, the true believer cannot ever lose his or her salvation; we will never fall from the state of justification. However, God may still chastise us for our sins. And so, we need to confess our sins every day; seek his forgiveness every day; and every day we must be careful to walk in his ways.