FORBIDDING SEXUAL SINS (vv. 1-30)
Chapter 17 has dealt with sin directly against God; now chapter 18 speaks of sin in relationship with other creatures, primarily humans, but also animals (v. 23). Moses was commanded to speak to the children of Israel, giving them God's message, “I am the Lord your God” (v. 2). This positive message itself should lift people's hearts far above the level of all the evil that surrounds them. Yet most of what follows is negative, telling Israel what they were not to do.
First, the evil practices they had seen in Egypt they were told not to do. Secondly, when they entered the land of Canaan they were not to do as the Canaanites did (vv. 2-3). The world was living in moral corruption, as it still is today, and the believer is not to conform to this kind of thing. They had come out of Egypt, as believers today have left the world that ignores the living God. Let them then take no part of the world with them. They were going to Canaan, but the Canaanites were living in corruption fully as bad as Egypt, for Canaan is typical of Christendom, where the profession of Christianity is accompanied by many glaring abuses of Christianity. These are circumstances distressing to one who has been called by God to a path of obedience to Him, but we should regard circumstances as a proving ground. Israel was tested in Canaan, and we cannot escape testing, but we have the Word of God to guard us and to strengthen us (vv. 4-5).
Any sexual relation with a blood relative is firmly forbidden (vv. 6-18). Even secular governments recognize the morality of this, so that incest is illegal. Abraham, married his half-sister (Genesis 20:11-12), but this was early in human history, when there was not the same danger of children being badly affected. “The laws of heredity show that in a fallen race, the inheritance of disease to which all are liable is intensified when similar tendencies are found in both parents” (Numerical Bible Genesis page 349). Time only increases the weakness that such disease brings in any genetic line, and of course this would be doubly increased by the marriage of two from the same line.
This evil defiled the assembly at Corinth when a man took his father's wife, that is, his stepmother (1 Corinthians 5:1). The assembly was told that such sin was not even named among the nations, and the man was put out from the assembly (v. 12). Only when the sin was judged and discontinued was the man restored (2 Corinthians 2:6-8).
These laws deal with matters that are morally wrong and are still wrong today. Though the believer is not in any sense “under law,” but “under grace,” this does nor mean that he is free to break over bounds of morality. Rather, it means that grace gives him both the desire and the ability to carry out the righteousness required by the law, without considering himself under the law's authority (Romans 8:3-4).
Adultery is just as evil as is incest (v. 20), and similarly forbidden. Verse 21 adds that Israelites were forbidden to offer their children to Molech. Though people spoke of this as a sacrifice, the practice did not spring from unselfish love for Molech, but from the selfish evil of wanting to get rid of a child. How evil it is today that many want to get rid of a child before it is born! Molech was an image with its arms outstretched, and people would place their children in its arms, while a fire was lit beneath. Then with drums and noisy music the cries of the child were drowned out as it was burned to death. Thus this religious wickedness sanctified the torture and murder of an unwanted child!
Closely related to this is the strong prohibition of the abominable practice of homosexuality (v. 22). God has provided the honorable institution of the marriage of a man and woman, yet people dare to abuse the very best that God has given, because of utter selfishness. We know too that such things bring painful repercussions (Romans 1:26-27. God is not mocked. People may feel they get away with evildoing, but whatever one sows he will also reap (Galatians 6:7).
It was even necessary that Israelites should be warned against the repulsive wickedness of having sexual relations with an animal (v. 23). But this, along with the other evils before mentioned, was practiced among the nations that God was to dispossess from Canaan (v. 24). In fact, it was because of the gross defilement of the land by these things that God was punishing the inhabitants by death or expulsion. If anyone in Israel were to be found guilty of such things, this would incur the death penalty also.
Just as this chapter begins, so it ends by the positive declaration, “I am the Lord your God” (v. 30). If Israel would only rightly recognize this wonderful, positive blessing, this would preserve them from all the negative evils of this chapter.