Form an introduction to the Hebrew code of prohibited degrees of marriage and of forbidden sins of lust. The formal and solemn declaration, I am the Lord your God, is made three times in these five verses. This places before the people the two thoughts:
1. That the Lord is holy, and they ought to be like him in holiness;
2. That the Lord has commanded holiness, and they ought to obey him by being holy. Because the Lord is their God, and they are his people, they are, negatively, to refrain from the vicious habits and lax customs prevalent in the land of Egypt wherein they dwelt, and in the land of Canaan whither they were going, the sensuality of which is indirectly condemned by the injunctions which command purity in contrast to their doings; and, positively, they are to keep God's statutes, and his judgments, as laid down in the following code, which if a man do, he shall live in them. The latter clause is of special importance, because it is repeated in the same connection by Ezekiel (Ezekiel 20:11, Ezekiel 20:13, Ezekiel 20:21), and in the Levitical confession in the Book of Nehemiah (Nehemiah 9:29), and is quoted by St. Paul in a controversial sense (Romans 10:5; Galatians 3:12). Its full meaning is that by obedience to God's commands man attains to a state of existence which alone deserves to be called true life—"the life which connects him with Jehovah through his obedience" (Clark). And this involves the further truth that disobedience results in death. Accordingly, St. Paul uses the text as being the testimony of the Law with regard to itself, that salvation by it is of works in contrast with faith. (Cf. Luke 10:28.) We have no evidence to tell us what were the doings of the land of Canaan in respect to the marriage relation, but this chapter is enough to show that the utmost laxity prevailed in it, and we may be sure that their religious rites, like those of Midian (Numbers 25:1-18), were penetrated with the spirit of licentiousness. With regard to the doings of the land of Egypt, we have fuller information. We know that among the Egyptians marriage with sisters and half-sisters was not only permissible, but that its propriety was justified by their religious beliefs, and practiced in the royal family (Died. Sic; 1:27; Die. Cass; 42). Other abominations condemned in this chapter (verse 23) also, as we know, existed there (Herod; 2:46), and if queens could be what in later times Cleopatra was, we may imagine the general dissoluteness of the people. Among Persians, Medes, Indians, Ethiopians and Assyrians, marriage with mothers and daughters was allowed, and from the time of Cambyses, marriage with a sister was regarded as lawful (Herod; Nehemiah 3:31). The Athenians and Spartans permitted marriage with half-sisters. All these concessions to lust, and ether unclean acts with which the heathen world was full (verse 22; Romans 1:27), were fallings away from the law of purity implanted in the heart of man and now renewed for the Hebrew people.