The many restrictions imposed on the metzora, as well as the detailed process of his purification, underscore the uniqueness and severity of tzara'at. Unlike other forms of tum'ah, which prevent an individual from entering various parts of the Beit Hamikdash, the metzora is forced to leave the entire machaneh Yisroel (camp of Israel).
The Gemara (Erachin 16B) links this isolation with the very cause of tzara'at itself. "Ma nishtana metzora sheamra Torah 'badad yesheiv michutz lemachaneh moshavo'? hu hivdil bein ish l'ishto, bein ish lerei-eihu, lefichoch amra Torah, 'badad yesheiv '" ("Why is a metzora different that the Torah states, 'He shall dwell alone; outside the camp shall be his dwelling'? He [through his slander] separated a husband from his wife, a man from his neighbor, therefore the Torah says, 'He shall dwell alone.'")
The slanderous metzora, who through his behavior fails to value the harmony of the community, must live in isolation.
The laws governing the metzora, however, extend far beyond his sequester. Based on the verse, "begadav yehiyu prumim verosho yehiye parua veal safam yateh" (Vayikrah 13:45) ("His garments shall be torn, the hair of his head shall be unshorn, and he shall cloak himself up to his lips"), the Gemara explains that a metzora must tear his garment and cover his head, as well as refrain from cutting his hair and greeting others (Moed Katan 15A).
The common theme linking these halachot implied by the Gemara and stated explicitly by the Rambam (Hilchot Tum'at Tzara'at 10:6) is Aveilut. The metzora is an avel and hence is bound by the many obligations and restrictions of mourning. In what sense, however, is a metzora an avel? Why is it that he must observe the traditions of aveilut?
Each member of Knesset Yisrael possesses a twofold kedushah-as an individual and as a vital part of the collectivity of Bnei Yisrael. A metzora, through his callous slander, severs his bond with the collective kedushah of Bnei Yisrael; it is as if part of him has died. Indeed, the Gemara states that "arba'ah chashuvin kemeis - ani umetzora..." (Nedarim 64B) ("four [types of people] are as if they are dead - a poor man, a metzora..."). Accordingly, the Torah mandates aveilut; the metzora mourns himself.
The onset of Yom Tov, however, marks a clear contrast between the avel and the metzora. Whereas the commencement of Yom Tov cancels aveilut, the Gemara (Moed Katan 14B), states that "noheig tzora'ato b'regel" ("the laws of the metzora apply on Yom Tov"). How do we understand this distinction? The ability of Yom Tov to suspend aveilut stems from the communal nature of Yom Tov: "asi aseh d'rabbim [Yom Tov] v'dachi aseh d'yachid [aveilus]" ("Let the public commandment of Yom Tov come and supersede the individual commandment of mourning"). A metzora, however, has severed his bond to the community. For him, the communal nature of Yom Tov cannot suspend the obligations and restrictions of tzara'at.
The plight of the metzora highlights the privilege and responsibility of kedushat Yisrael. May we be the worthy beneficiaries of this transcendent gift.