A metzora, a person afflicted with tzora’as, must remain outside the encampment of the Jewish people until his tzora’as has healed. The metzora’s isolation from the Jewish camp reflects his sorry spiritual state. He is a gossiper, who brings strife and conflict between people (see Rashi on Vayikra 13:46); he is thus the polar opposite of holiness, which is characterized by unity and harmony. His distance from the Jewish camp is the natural outcome of his detachment and distance from anything holy.This explains why the Torah says that for the metzora’s purification, “he shall be brought to the kohen.” This verse is difficult to understand on a literal level, inasmuch as the impure metzora may not enter the camp to come or be brought to the kohen, and instead the kohen must go out to him (as the following verse indeed states, “the kohen shall go outside the camp.”)

With these words, however, the Torah hints to the metzora’s spiritual purification. The metzora is so removed from holiness that it’s possible that he has no conscious desire to live a holy Jewish lifestyle. In fact, he may want to do just the opposite. Nevertheless, the Torah foretells and guarantees that “he shall be brought to the kohen”—whether he wills so or not, for even a person as distant as a metzora will ultimately do Teshuva, and return to G-d and His ways, (as explained in Tanya, Chapter 39.) Before the coming of Moshiach, G-d will arouse a spirit of Teshuva in the heart of every single Jew, bringing him to the kohen for purification, as it were, even if he has not yet sought out this purification on his own.

—Likutei Sichos vol. 7. pp. 100-102