The Torah introduces the concept of tzara’at ha-adam – the form of tzara’at that affects people’s skin – by mentioning that it is manifest in three forms of discoloration: se’eit, sapachat and baheret (13:2). Chazal (Negaim 1:1, Shavuot 5b-6b) understood the Torah as actually referring to four different shades of the color white. The word sapachat is interpreted to mean “secondary,” such that the Torah here speaks of two primary colors – se’eit and baheret – each of which also has a secondary color which likewise constitutes a tzara’at infection. The four colors are snow-white, sid ha-heikhal (the color of the white plaster used for the walls of the Beit Ha-mikdash), the color of egg whites, and the color of wool of a newborn lamb. The Tanna’im disagree as to which of these four colors are the primary white colors and which are secondary, but all agree that a skin discoloration qualifies as tzara’at only if it is one of these forms of white.
Many have noted the irony in the fact that tzara’at, which brings the strictest of all forms of tum’a (impurity), manifests itself specifically through the color white, which is a common symbol of purity. God proclaims through the prophet Yeshayahu (1:18), “If your sins are like crimson, they will be white like snow; if they are as red as dye, they will be like wool.” And the Mishna in Masekhet Yoma (68b) tells that a red thread (“lashon shel zehorit”) was hung in the Beit Ha-mikdash on Yom Kippur and would miraculously turn white to indicate to the people that they achieved forgiveness. If the whiteness of snow and wool are symbols of atonement and purity, why is it that the impurity of tzara’at is caused specifically by skin turning this color?
Some have explained this irony based on the famous association between tzara’at and interpersonal offenses, specifically lashon ha-ra (negative speech about other people), which is often the outgrowth of arrogance and snobbery. The symbolic message of tzara’at is precisely that “purity” – genuine spiritual devotion – can sometimes lead to the impurity of arrogance and disdain for other people. The white discoloration indicates that the individual’s purity has resulted in impurity, that his quest for piety brought him to impious condescension and contempt for other people. Lashon ha-ra is a sin to which “pure” individuals are especially prone, as their enthusiastic pursuit of spiritual excellence can so easily cause them to look disdainfully upon, and speak disdainfully about, people who do not pursue piety with the same vigor and passion that they possess. Tzara’at, then, warns of the dangerous pitfalls of purity, reminding us that our efforts to grow and achieve must never lead us to arrogant and self-righteous disdain for other people.