Leviticus 13:39

If a skin rash had pus or swelling, it was probably an infection (Leviticus 13:42). If it only appeared as a white area, it was probably vitiligo (leucoderma). This harmless condition causes patches of skin to lose color.

a skin disease: The Hebrew word tsaraʿat refers to more than Hansen’s disease (leprosy), which is rare and severely disfiguring. In Leviticus, the word describes many different conditions. These include:

• an open sore (13:10),

• a boil (13:18),

• a burn (13:24),

• a sore on the head or chin (13:29),

• shiny white patches (13:38), or

• unusual baldness (13:40).

A key test was whether the condition spread to other parts of the body (13:5–8). If it did, they quarantined the person while the disorder lasted (13:46). Not only people, but also clothing and even buildings could become infected (13:47–59; 14:33–53).

If a man . . . or a woman have in the skin of their flesh bright spots--This modification of the leprosy is distinguished by a dull white color, and it is entirely a cutaneous disorder, never injuring the constitution. It is described as not penetrating below the skin of the flesh and as not rendering necessary an exclusion from society. It is evident, then, that this common form of leprosy is not contagious; otherwise Moses would have prescribed as strict a quarantine in this as in the other cases. And hereby we see the great superiority of the Mosaic law (which so accurately distinguished the characteristics of the leprosy and preserved to society the services of those who were laboring under the uncontagious forms of the disease) over the customs and regulations of Eastern countries in the present day, where all lepers are indiscriminately proscribed and are avoided as unfit for free intercourse with their fellow men.

We have here,
I. Provisos that neither a freckled skin nor a bald head should be mistaken for a leprosy, Lev 13:38-41. Every deformity must not forthwith be made a ceremonial defilement. Elisha was jeered for his bald head (Kg2 2:23); but it was the children of Bethel, that knew not the judgments of their God, who turned it to his reproach.
II. A particular brand set upon the leprosy if at any time it did appear in a bald head: The plague is in his head, he is utterly unclean, Lev 13:44. If the leprosy of sin have seized the head, if the judgment be corrupted, and wicked principles which countenance and support wicked practices, be embraced, it is an utter uncleanness, from which few are ever cleansed. Soundness in the faith keeps the leprosy from the head, and saves conscience from being shipwrecked.
III. Directions what must be done with the convicted leper. When the priest, upon mature deliberation, had solemnly pronounced him unclean,
1. He must pronounce himself so, Lev 13:45. He must put himself into the posture of a mourner and cry, Unclean, unclean. The leprosy was not itself a sin, but it was a sad token of God's displeasure and a sore affliction to him that was under it. It was a reproach to his name, put a full stop to his business in the world, cut him off from conversation with his friends and relations, condemned him to banishment till he was cleansed, shut him out from the sanctuary, and was, in effect, the ruin of all the comfort he could have in this world. Heman, it would seem, either was a leper or alludes to the melancholy condition of a leper, Psa 88:8, etc. He must therefore, (1.) Humble himself under the mighty hand of God, not insisting upon his cleanness when the priest had pronounced him unclean, but justifying God and accepting the punishment of his iniquity. He must signify this by rending his clothes, uncovering his head, and covering his upper lip, all tokens of shame and confusion of face, and very significant of that self-loathing and self-abasement which should fill the hearts of penitents, the language of which is self-judging. Thus must we take to ourselves the shame that belongs to us, and with broken hearts call ourselves by our own name, Unclean, unclean - heart unclean, life unclean, unclean by original corruption, unclean by actual transgression - unclean, and therefore worthy to be for ever excluded from communion with God, and all hope of happiness in him. We are all as an unclean thing (Isa 64:6) - unclean, and therefore undone, if infinite mercy do not interpose. (2.) He must give warning to others to take heed of coming near him. Wherever he went, he must cry to those he saw at a distance, "I am unclean, unclean, take heed of touching me." Not that the leprosy was catching, but by the touch of a leper ceremonial uncleanness was contracted. Every one therefore was concerned to avoid it; and the leper himself must give notice of the danger. And this was all that the law could do, in that it was weak through the flesh; it taught the leper to cry, Unclean, unclean, but the gospel has put another cry into the lepers' mouths, Luk 17:12, Luk 17:13, where we find ten lepers crying with a loud voice, Jesus, Master, have mercy on us. The law only shows us our disease; the gospel shows us our help in Christ.
2. He must then be shut out of the camp, and afterwards, when they came to Canaan, out of the city, town, or village, where he lived, and dwell alone (Lev 13:46), associating with none but those that were lepers like himself. When king Uzziah became a leper, he was banished from his palace, and dwelt in a separate house, Ch2 26:21. And see Kg2 7:3. This typified the purity which ought to be preserved in the gospel church, by the solemn and authoritative exclusion of scandalous sinners, that hate to be reformed, from the communion of the faithful. Put away from among yourselves that wicked person, Co1 5:13.

If a man or woman. What is here spoken of is not the baldness which so often occurs in old age; but that loss of hair, which is the consequence of leprosy, is distinguished from any other, the cause of which may be some indisposition, and which yet does not pollute a man. But, inasmuch as some kinds of baldness do not so greatly differ at first sight from leprosy, -- such, for instance, as ophiasis and alopecia [8] -- it is therefore necessary to distinguish them.

The scall shall he not shave - Lest the place should be irritated and inflamed, and assume in consequence other appearances besides those of a leprous infection; in which case the priest might not be able to form an accurate judgment.

Then the priest shall look,.... Upon the man or woman that has these spots, and upon the spots themselves, and examine them of what kind they are:

and, behold, if the bright spots in the skin of their flesh be darkish white; their whiteness is not strong, as Jarchi observes; but dusky and obscure, or "contracted" (w); small white spots, not large and spreading:

it is a freckled spot that grows in the skin; a kind of morphew, which the above writer describes as a sort of whiteness which appears in the flesh of a ruddy man:

he is clean; from leprosy; this is observed, lest a person that is freckled and has a morphew should be mistaken for a leprous person; as every man that has some spots, failings, and infirmities, is not to be reckoned a wicked man.

(w) "costractae", Junius & Tremellius, Piscator.

Darkish white, or contracted, or confined to the place where they are, and white.

Harmless leprosy. - This broke out upon the skin of the body in בּהרת plaits, "white rings." If these were dull or a pale white, it was the harmless bohak, ἀλφός (lxx), which did not defile, and which even the Arabs, who still call it bahak, consider harmless. It is an eruption upon the skin, appearing in somewhat elevated spots or rings of inequal sizes and a pale white colour, which do not change the hair; it causes no inconvenience, and lasts from two months to two years.