John Wesley on Leviticus 14:37

In the walls of the house - This was an extraordinary judgment of God peculiar to this people, either as a punishment of their sins, which were much more sinful and inexcusable than the sins of other nations; or as a special help to repentance, which God afforded them above other people; or as a token of the mischievous nature of sin, typified by leprosy, which did not only destroy persons, but their habitations also: Hollow streaks - Such as were in the bodies of leprous persons.