I.Concerning the plague of leprosy we may observe in general, 1. That it was rather an uncleanness than a disease; or, at least, so the law considered it, and therefore employed not the physicians but the priests about it. Christ is said to cleanse lepers, not to cure them. We do not read of any that died of the leprosy, but it rather buried them alive, by rendering them unfit for conversation with any but such as were infected like themselves. Yet there is a tradition that Pharaoh, who sought to kill Moses, was the first that ever was struck with this disease, and that he died of it. It is said to have begun first in Egypt, whence it spread into Syria. It was very well known to Moses, when he put his own hand into his bosom and took it out leprous. 2. That it was a plague inflicted immediately by the hand of God, and came not from natural causes, as other diseases; and therefore must be managed according to a divine law. Miriam's leprosy, and Gehazi's, and king Uzziah's, were all the punishments of particular sins: and, if generally it was so, no marvel there was so much care taken to distinguish it from a common distemper, that none might be looked upon as lying under this extraordinary token of divine displeasure but those that really were so. 3. That it is a plague not now known in the world; what is commonly called the leprosy is of a quite different nature. This seems to have been reserved as a particular scourge for the sinners of those times and places. The Jews retained the idolatrous customs they had learnt in Egypt, and therefore God justly caused this with some others of the diseases of Egypt to follow them. Yet we read of Naaman the Syrian, who was a leper, Kg2 5:1. 4. That there were other breakings-out in the body which did very much resemble the leprosy, but were not it, which might make a man sore and loathsome and yet not ceremonially unclean. Justly are our bodies called vile bodies, which have in them the seeds of so many diseases, by which the lives of so many are made bitter to them. 5. That the judgment of it was referred to the priests. Lepers were looked upon as stigmatized by the justice of God, and therefore it was left to his servants the priests, who might be presumed to know his mark best, to pronounce who were lepers and who were not. All the Jews say, "Any priest, though disabled by a blemish to attend the sanctuary, might be a judge of the leprosy, provided the blemish were not in his eye. And he might" (they say) "take a common person to assist him in the search, but the priest only must pronounce the judgment." 6. That it was a figure of the moral pollution of men's minds by sin, which is the leprosy of the soul, defiling to the conscience, and from which Christ alone can cleanse us; for herein the power of his grace infinitely transcends that of the legal priesthood, that the priest could only convict the leper (for by the law is the knowledge of sin), but Christ can cure the leper, he can take away sin. Lord, if thou wilt, thou canst make me clean, which was more than the priests could do, Mat 8:2. Some think that the leprosy signified, not so much sin in general as a state of sin, by which men are separated from God (their spot not being the spot of God's children), and scandalous sin, for which men are to be shut out from the communion of the faithful. It is a work of great importance, but of great difficulty, to judge of our spiritual state: we have all cause to suspect ourselves, being conscious to ourselves of sores and spots, but whether clean or unclean is the question. A man might have a scab (Lev 13:6) and yet be clean: the best have their infirmities; but, as there were certain marks by which to know that it was a leprosy, so there are characters of such as are in the gall of bitterness, and the work of ministers is to declare the judgment of leprosy and to assist those that suspect themselves in the trial of their spiritual state, remitting or retaining sin. And hence the keys of the kingdom of heaven are said to be given to them, because they are to separate between the precious and the vile, and to judge who are fit as clean to partake of the holy things and who as unclean must be debarred from them.

II.Several rules are here laid down by which the judgment of the priest must be governed. 1. If the sore was but skin-deep, it was to be hoped it was not the leprosy, Lev 13:4. But, if it was deeper than the skin, the man must be pronounced unclean, Lev 13:3. The infirmities that consist with grace do not sink deep into the soul, but the mind still serves the law of God, and the inward man delights in it, Rom 7:22, Rom 7:25. But if the matter be really worse than it shows, and the inwards be infected, the case is dangerous. 2. If the sore be at a stay, and do not spread, it is no leprosy, Lev 13:4, Lev 13:5. But if it spread much abroad, and continue to do so after several inspections, the case is bad, Lev 13:7, Lev 13:8. If men do not grow worse, but a stop be put to the course of their sins and their corruptions be checked, it is to be hoped they will grow better; but if sin get ground, and they become worse every day, they are going downhill. 3. If there was proud raw flesh in the rising, the priest needed not to wait any longer, it was certainly a leprosy, Lev 13:10, Lev 13:11. Nor is there any surer indication of the badness of a man's spiritual state than the heart's rising in self-conceit, confidence in the flesh, and resistance of the reproofs of the word and strivings of the Spirit. 4. If the eruption, whatever it was, covered all the skin from head to foot, it was no leprosy (Lev 13:12, Lev 13:13); for it was an evidence that the vitals were sound and strong, and nature hereby helped itself, throwing out what was burdensome and pernicious. There is hope in the small-pox when they come out well: so if men freely confess their sins, and hide them not, there is no danger comparable to theirs that cover their sins. Some gather this from it, that there is more hope of the profane than of hypocrites. The publicans and harlots went into the kingdom of heaven before scribes and Pharisees. In one respect, the sudden breakings-out of passion, though bad enough, are not so dangerous as malice concealed. Others gather this, that, if we judge ourselves, we shall not be judged; if we see and own that there is no health in us, no soundness in our flesh, by reason of sin, we shall find grace in the eyes of the Lord. 5. The priest must take time in making his judgment, and not give it rashly. If the matter looked suspicious, he must shut up the patient seven days, and then seven days more, that his judgment might be according to truth. This teaches all, both ministers and people, not to be hasty in their censures, nor to judge any thing before the time. If some men's sins go before unto judgment, the sins of others follow after, and so men's good works; therefore let nothing be done suddenly, Ti1 5:22, Ti1 5:24, Ti1 5:25. 6. If the person suspected was found to be clean, yet he must wash his clothes (Lev 13:6), because he had been under the suspicion, and there had been in him that which gave ground for the suspicion. Even the prisoner that is acquitted must go down on his knees. We have need to be washed in the blood of Christ from our spots, though they be not leprosy-spots; for who can say, I am pure from sin? though there are those who through grace are innocent from the great transgression.

If the leprosy have covered all his flesh, he shall pronounce him clean - Why is it that the partial leper was pronounced unclean, and the person totally covered with the disease clean? This was probably owing to a different species or stage of the disease; the partial disease was contagious, the total not contagious. That there are two different species or degrees of the same disease described here, is sufficiently evident. In one, the body was all covered with a white enamelled scurf; in the other, there was a quick raw flesh in the risings. On this account the one might be deemed unclean, i. e., contagious, the other not; for contact with the quick raw flesh would be more likely to communicate the disease than the touch of the hard dry scurf. The ichor proceeding from the former, when brought into contact with the flesh of another, would soon be taken into the constitution by means of the absorbent vessels; but where the whole surface was perfectly dry, the absorbent vessels of another person coming in contact with the diseased man could imbibe nothing, and therefore there was comparatively no danger of infection. Hence that species or stage of the disease that exhibited the quick raw rising was capable of conveying the infection for the reasons already assigned, when the other was not. Dr. Mead thus accounts for the circumstance mentioned in the text. See on Lev 13:18 (note). As the leprosy infected bodies, clothes, and even the walls of houses, is it not rational to suppose that it was occasioned by a species of animalcula or vermin burrowing under the skin? Of this opinion there are some learned supporters.

Or if the raw flesh turn again,.... Changes its colour, from redness, which is in raw flesh:

and be changed unto white: and does not look ruddy as flesh in common does, nor red and fiery, as raw and proud flesh, but is white, of the same colour with the swelling or scab:

he shall come unto the priest; again, and show himself, even though he was before by him pronounced clean.

if the rising be white--This BRIGHT WHITE leprosy is the most malignant and inveterate of all the varieties the disease exhibits, and it was marked by the following distinctive signs: A glossy white and spreading scale, upon an elevated base, the elevation depressed in the middle, but without a change of color; the black hair on the patches participating in the whiteness, and the scaly patches themselves perpetually enlarging their boundary. Several of these characteristics, taken separately, belong to other blemishes of the skin as well; so that none of them was to be taken alone, and it was only when the whole of them concurred that the Jewish priest, in his capacity of physician, was to pronounce the disease a malignant leprosy. If it spread over the entire frame without producing any ulceration, it lost its contagious power by degrees; or, in other words, it ran through its course and exhausted itself. In that case, there being no longer any fear of further evil, either to the individual himself or to the community, the patient was declared clean by the priest, while the dry scales were yet upon him, and restored to society. If, on the contrary, the patches ulcerated and quick or fungous flesh sprang up in them, the purulent matter of which, if brought into contact with the skin of other persons, would be taken into the constitution by means of absorbent vessels, the priest was at once to pronounce it an inveterate leprosy. A temporary confinement was them declared to be totally unnecessary, and he was regarded as unclean for life [DR. GOOD]. Other skin affections, which had a tendency to terminate in leprosy, though they were not decided symptoms when alone, were: "a boil" (Lev 13:18-23); "a hot burning,"--that is, a fiery inflammation or carbuncle (Lev 13:24-28); and "a dry scall" (Lev 13:29-37), when the leprosy was distinguished by being deeper than the skin and the hair became thin and yellow.