When ye be come into the land of Canaan. — We have here the first of four instances in Leviticus of a law being given prospectively, having no immediate bearing on the condition of the people of Israel (see Leviticus 19:23; Leviticus 23:10; Leviticus 25:2). This may be the reason why it is separated from the law of leprous men and garments, which we should naturally expect it would follow, instead of being preceded by the law of cleansing, and why it occupies the position of an appendix. Because it is here said “the land of Canaan,” the authorities during the second Temple maintained that this supernatural plague of leprous houses was peculiar to Palestine, and was unknown in any other country. They moreover adduce the words “in a house of the land of your possession” to account for the fact that houses in Palestine not in the possession of the Israelites, — i.e., houses of Gentiles — were exempt from this distemper, that the synagogues throughout the country which had no official dwelling-houses attached to them were never visited by this loathsome disease, and that none of the houses in Jerusalem were ever afflicted with it, because the holy city was never divided among the tribes. Whatever we may think of their interpretation, the testimony of these eye-witnesses who had to administer the laws of leprosy, that out of Palestine, that in certain houses in Palestine, and that in the whole of Jerusalem, this kind of distemper was unknown, remains unshaken.
And I put the plague of leprosy. — The plague is here described as a supernatural one, proceeding from the immediate hand of God. Ordinary leprosy, as we are told by the authorities in the time of Christ, comes upon man for the following sins: “for idolatry, for profaning the name of the Lord, unchastity, theft, slander, false witness, false judgment, perjury, infringing the borders of a neighbour, devising malicious plans, or creating discord between brothers.” House leprosy is sent by God if the owner of a plot of land on the sacred soil builds his house with materials unlawfully acquired. Hence the ancient Chaldee Version of Jonathan renders the first part of this verse by, “And if there be a man who buildeth his house with stolen goods, then I will put the plague,” &c.