Charles Ellicott Commentary Leviticus 14:34

"When ye are come into the land of Canaan, which I give to you for a possession, and I put the plague of leprosy in a house of the land of your possession;" — Leviticus 14:34 (ASV)

When you come into the land of Canaan. —We have here the first of four instances in Leviticus where a law was given prospectively, having no immediate bearing on the condition of the people of Israel (Leviticus 23:10; Leviticus 25:2). This may be the reason why it is separated from the law concerning leprous men and garments, which we would naturally expect it to 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 also cite 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—that is, houses of Gentiles—were exempt from this disease; that the synagogues throughout the country, which had no official residences 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 eyewitnesses who had to administer the laws of leprosy—that this kind of disease was unknown outside of Palestine, in certain houses in Palestine, and in all of Jerusalem—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 a person for the following sins: “for idolatry, for profaning the name of the Lord, unchastity, theft, slander, false witness, false judgment, perjury, violating a neighbor’s boundaries, 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 unlawfully acquired materials. Therefore, the ancient Chaldee Version of Jonathan translates the first part of this verse as, “And if there is a man who builds his house with stolen goods, then I will put the plague,” etc.