Leviticus 13:3

And the priest shall look at the plague in the skin of the flesh,--and if the hair of the stricken place be turned to whiteness, and the appearance of the plague be deeper (than the surface), and be whiter than the skin of his flesh, like snow, it is the plague of leprosy; and the priest having inspected him shall make him to be unclean.

AND THE APPEARANCE OF THE PLAGUE BE DEEPER THAN THE SKIN OF THE FLESH. “Every white color appears deep [in contrast to the darker color surrounding it], just as a color illuminated by the sun appears deeper than the shadow.” This is Rashi’s language. For this reason when the Rabbi [Rashi] reached the following verse, stating, And if the bright spot be white in the skin of his flesh, and the appearance thereof be not deeper than the skin, are based: (a) Any of the four colors of white (see Note 105) which appears in the skin of the flesh, does not of itself render the person impure, unless in addition it has one of the three symptoms of impurity, which are: if the plague has turned a minimum of two black hairs in the white patch in the flesh to white, or some “quick flesh” has appeared in the middle of the plague, or, if not having had one of these symptoms to begin with, the person was shut up for seven days, and then it was seen that the white patch of the plague had spread in the skin. (b) If any of these four colors appear in a place where there was an inflammation or a burning inflammation, the person is rendered impure only by means of one of these two symptoms: hair changing color from black to white, or the spreading of the white patch of the plague in the skin. The appearance of “quick flesh” in this case is not a sign of impurity. (c) If a plague appears in the hair, the symptoms of impurity are one of two: if the plague has caused a minimum of two hairs to turn gold-colored, or if it has spread in the skin. (d) A special lengthy discussion appears in Ramban (further in Verse 29) as to the precise nature of the plague which the Torah calls nethek (Verse 30), and which laws regulate it. Other laws pertinent to these discussions are clearly set forth in the text. Finally, it should be noted that a person shut up or quarantined for a week by the priest is rendered unclean in every respect as a leper that is certified unclean, except that he need not go with unkempt hair and rent garments; also, if declared “clean” by the priest at the end of the week he need not do the cutting off of the hair and the bringing of the bird-offerings etc., as they are required of the leper that had been certified unclean when healed of his leprosy (see further Chapter 14) (Megillah 8 b). he wrote, “I do not know the meaning of this.” The sense of Rashi’s statement is as follows: It appeared to him difficult, for since the bright spot is …

ומראה הנגע עמוק, white.

נגע צרעת היא. The Torah repeats this same expression twice in successive verses, and also the expression צרעת היא is repeated both in verse 8 and verse 11. Sometimes, as here and as in verse 22, the word נגע is added. The reason may be that this affliction, in common with other afflictions, is something that develops in stages. Just as the affliction intensifies gradually in its early stages, so it gradually becomes weaker on the way to healing. When it is already a long-standing affliction it is referred to as צרעת יושנת, whereas when it is in its opening stages it is called simply נגע. When it is a fully fledged affliction it is called נגע צרעת. When it is in the process of waning it is already referred to as נרפא הצרעת, an affliction which has healed. When it has healed completely it is referred to as נרפא הנתק. Seeing that this type of affliction is perceived as a warning signal from G’d to the individual experiencing it, i.e. he is reminded to get rid of negative characteristics, the Talmud refers to it as מזבח כפרה “an altar serving as atonement.” The period of isolation serves to remind the afflicted person to review what he may have been guilty of. This concept has been spelled out in Job 36,10 as ויגל אותם למוסר ויאמר כי ישובון מאון, “He opens their understanding by discipline, and orders them back from mischief.”