Why is "You shall not commit adultery" in the Ten Commandments?

In the Old Testament, adultery, unfaithfulness towards the spouse for the satisfaction of lust, was to be dealt with most severely. According to the law of Sinai this sin had to be punished with death (Lev. 20: 10; Deut. 22: 22-24). In the first place the law contained God's regulations for the outward and social life of His earthly people, and for this reason only the accomplished offence was to be punished, even though the tenth commandment forbad the coveting of the neighbour's wife (as well as all his possessions. Ex. 20: 17). If a Jew kept the commandment not to commit adultery, he was acting according to God's will and contributed towards the maintenance of the people's community according to God's order. Fear of the punishment threatened certainly contributed to this. However, the mere outward observance of this and all the other commandments could not justify him before God.

In the Old Testament, adultery, unfaithfulness towards the spouse for the satisfaction of lust, was to be dealt with most severely. According to the law of Sinai this sin had to be punished with death (Lev. 20:10; Deut. 22:22-24). In the first place the law contained God's regulations for the outward and social life of His earthly people, and for this reason only the accomplished offence was to be punished, even though the tenth commandment forbad the coveting of the neighbour's wife (as well as all his possessions. Ex. 20:17). If a Jew kept the commandment not to commit adultery, he was acting according to God's will and contributed towards the maintenance of the people's community according to God's order. Fear of the punishment threatened certainly contributed to this. However, the mere outward observance of this and all the other commandments could not justify him before God.

The seventh commandment safeguards the purity of human life. "Adultery" here has the widest sense, covering what are considered to be lesser forms of this sin between the sexes. The history of peoples shows those who have widely practised this evil have degraded themselves both physically and mentally, and out of it spring a host of other ills.

Following upon the other references to the law, the Lord Jesus now quotes the seventh commandment: “Thou shalt not commit adultery” (Ex. 20:14; Deut. 5:18). Marriage is something into which two persons enter for life, and ever since creation it has enjoyed God's special care. According to the New Testament it is a picture of the relationship between Christ and His assembly, marked by divine love and human devotion.

But what has become of marriage through sin! It was not the will of God that Lamech, Abraham, Jacob, Solomon and other men of the Old Testament should have several wives at the same time, and this only brought distress into their families. How serious was the adultery David committed with Bathsheba! And how are things today with regard to matrimonial morals — not only in the world, but also among Christians? In recent decades Biblical standards in society have been systematically done away with in this area too.

Following upon the other references to the law, the Lord Jesus now quotes the seventh commandment: "Thou shalt not commit adultery" (Ex. 20: 14; Deut. 5: 18). Marriage is something into which two persons enter for life, and ever since creation it has enjoyed God's special care. According to the New Testament it is a picture of the relationship between Christ and His assembly, marked by divine love and human devotion.

But what has become of marriage through sin! It was not the will of God that Lamech, Abraham, Jacob, Solomon and other men of the Old Testament should have several wives at the same time, and this only brought distress into their families. How serious was the adultery David committed with Bathsheba! And how are things today with regard to matrimonial morals-not only in the world, but also among Christians? In recent decades Biblical standards in society have been systematically done away with in this area too.

Marriage. — Now marriage was God's provision for His creatures, — instituted before the Fall; continued by God after it; upheld as inviolable by Him before the law (Gen. 12:17, 20:3); guarded by express enactments under the law (Ex. 20:14, 17); its sanctity being reaffirmed by the Lord (Matt. 19:3-9); and its honourable estate for all declared by New Testament revelation (Heb. 13:4). Much must Adam have felt that he had lost of temporal enjoyment through the Fall. This blessing, however, was preserved to him, and to his descendants, as God's original institution for the happiness and welfare of His human creatures on earth.

But why, it may be asked, were such terms proposed to Israel, when they had no strength to keep them? God saw that it would be good and wholesome for man to know the truth about himself, and the nature and extent of God's claims upon him; and for this end He gave the law. It was the perfect standard of what God required of man, of what man ought to be, and the prohibition of that to which he was strongly inclined. The ten commandments, for the most part, are like an interdict on the human will. "Thou shall not." … "Thou shalt not," is the stern, prohibitory voice of the moral law.

Then (Exodus 20) are uttered those wonderful ten commandments which are the great centre of divine communications through Moses — the fundamental expression of God's law. On this, being so thoroughly familiar to all, I of course do not enlarge. We know from our Lord Jesus its moral summary and essence — the love of God, and the love of man. But it was presented here for the most part in a way that betrayed the condition of man — not in positive precepts but in negative ones — a most humbling proof of man's estate. He loved sin so well that God had to interdict it. In the greater part of the ten commandments, in short, it was not "Thou shalt," but "Thou shalt not." That is, it was a prohibition of man's will. He was a sinner, and nothing else.

The law was like a straight edge given by God to make manifest the crookedness of man. "[The] law entered that the offence might abound " (Rom. 5:20), that is, not to increase sin, but to show its offensiveness, and to bring it home to the soul. "By [the] law is the knowledge of sin." Rom. 3:20. The apostle said that he would not have known lust had not the law said, "Thou shalt not covet." Rom. 7:7. The object of the law therefore was to evince the heinousness of sin, while it was a test of the obedience of man to God. It was given to Israel only, the one nation which was under God's special dealings, and in which He was trying man in the flesh. The heading of the ten commandments is "I am the Lord thy God, which have brought thee out of the land of Egypt, out of the house of bondage," and this could apply only to the Israelites. Again, God says, "You only have I known of all the families of the earth: therefore I will punish you for all your iniquities." Amos 3:2. The Gentiles are described as not having the law, Rom. 2:14, though they had the work of the law written in their hearts, and a conscience which bore witness when they did wrong. As the Gentiles became associated with Israel, and heard what God required morally of man, they doubtless became more or less responsible according to the light received. But greater light having come in, the Galatian Christians are sharply rebuked for putting themselves under law, where, as Gentiles, they never had been. Some things forbidden in the law were wrong intrinsically, such as theft, murder, etc.; but other things were wrong only because God had forbidden them, such as the command to abstain from eating certain creatures called 'unclean.'

Yet it was perfectly right and in keeping with the claims of His throne that His will should be made known. God had to tell men what His will for them was; they had turned their backs on Him and were doing their own will, and that was a challenge to God's majesty. The world belonged to God, "The earth is the Lord's," and men in it are His responsible creatures, and He had, in justice and for the maintenance of His throne of government, to make known His will, and so we have the ten commandments, God's will for men here on the earth, summed up in these two sentences, "Thou shalt love the Lord thy God with all thy heart, and thy neighbour as thyself." Men broke that law, and all through the generations to the coming of the Lord Jesus Christ they broke it, and that which was ordained for a blessing became a curse.