Hollow strakes ... - Rather, depressed spots of dark green or dark red, appearing beneath (the surface of) the wall.

And he shall look on the plague,.... That which is taken or suspected to be one, being pointed unto by the owner of the house:

and, behold, if the plague be in the walls of the house; for there it chiefly was, if not solely; and from hence Gersom infers that it must be a walled house, and that it must have four walls, neither more nor fewer; and with this agrees the Misnah (l), according to which it must be four square; the signs of which were, when it appeared:

with hollow strakes, greenish or reddish, which in sight are lower than the wall: these signs agree with the other signs before given of leprosy in men and garments; the first, the hollow strakes, which are explained by being lower in appearance than the wall, a sort of corrosion or eating into it, which made cavities in it, answer to the plague being deeper than the skin of the flesh in men; and the colours greenish or reddish, or exceeding green or red, as Gersom, are the same with those of the leprosy in clothes; and some such like appearances are in saltpetre walls, or in walls eaten by saline and nitrous particles; and also by sulphureous, oily, and arsenical ones, as Scheuchzer observes (m), and are not only tending to ruin, but unhealthful, as if they had rather been eaten by a canker or spreading ulcer; who also speaks of a fossil, called in the German language "steingalla", that is, the gall of stones, by which they are easily eaten into, because of the vitriolic salt of the fire stone, which for the most part goes along with that mineral, which is dissolved by the moist air. Though this leprosy, in the walls of a house, seems not to have risen from any natural causes, but was from the immediate hand of God; and there have been strange diseases, which have produced uncommon effects on houses, and other things: in the times of Narses is said to be a great plague, especially in the province of Liguria, and on a sudden appeared certain marks and prints on houses, doors, vessels, and clothes, which, if they attempted to wash off, appeared more and more (n).

(l) Misn. Nagaim, c. 12. sect. 1, 2.((m) Physica Sacra, vol. 3. p. 330, 331. (n) Warnefrid de Gest. Longobard. l. 2. apud Scheuchzer. ib.

If the leprous spot appeared in "greenish or reddish depressions, which looked deeper than the wall," the priest was to shut up the house for seven days. If after that time he found that the mole had spread on the walls, he was to break out the stones upon which it appeared, and remove them to an unclean place outside the town, and to scrape the house all round inside, and throw the dust that was scraped off into an unclean place outside the town. He was then to put other stones in their place, and plaster the house with fresh mortar.

And he shall look on the plague, and, behold, if the plague be in the walls of the house with hollow streaks, greenish or reddish, which in sight are lower than the wall;

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.

14:33-53 The leprosy in a house is unaccountable to us, as well as the leprosy in a garment; but now sin, where that reigns in a house, is a plague there, as it is in a heart. Masters of families should be aware, and afraid of the first appearance of sin in their families, and put it away, whatever it is. If the leprosy is got into the house, the infected part must be taken out. If it remain in the house, the whole must be pulled down. The owner had better be without a dwelling, than live in one that was infected. The leprosy of sin ruins families and churches. Thus sin is so interwoven with the human body, that it must be taken down by death.