Defile not ye yourselves in any of these things: for in all these the nations are defiled which I cast out before you:
In all these the nations are defiled ... Ancient history gives many appalling proofs that the enormous vices described in this chapter were very prevalent-nay, were regularly practiced from religious motives in the temples of Egypt and the groves of Canaan; and it was these gigantic social disorders that occasioned the expulsion of which the Israelites were, in the hands of a righteous and retributive Providence, the appointed instruments (Genesis 15:16). The strongly figurative language of 'the land itself vomiting out her inhabitants,' as the stomach disgorges a deadly poison, shows the hopeless depth of their moral corruption.
Verse 30. Therefore shall ye keep mine ordinance. In giving the Israelites these particular institutions, God was only re-delivering the law imprinted on the natural heart of man; because there is every reason to believe that the incestuous alliances and unnatural crimes prohibited in this chapter were forbidden to all men by a law expressed or understood from the beginning of the world, or at least from the era of the flood; since God threatens to condemn and punish, in a manner so sternly severe, these atrocities in the practice of the Canaanites and their neighbours, who were not subject to the laws of the Hebrew nation, (cf. 'Hebrew Wife:' pp. 123-125; Graves, 'Lectures on the Pentateuch,' 2:, pp. 49-52; Dr. Watson's 'Apology for the Bible,' Letter
i., p. 9; Paley's 'Sermons on Several Subjects,' Sermon 29:)