One of the proofs that we treat tzara’at (most closely translated, leprosy) as a spiritual, not natural, disease is the fact that only a kohen may determine that one has been afflicted. Our second parasha begins with the purification process from tzara’at, which also centers on the kohen. Commentaries are bothered by an apparent contradiction between the p’sukim. First it says that the metzora (leper) is brought to the kohen (Vayikra 14:2). Yet, the Torah continues that "the kohen goes outside the encampment" to check the metzora (ibid.:3). Who goes to whom?
The Seforno gives a technical answer. The kohen sees him outside the encampment; however, the metzora approaches the kohen as much as he can to minimize the kohen’s travel. The Ramban proposes two explanations. One is that bringing the kohen refers solely to the fact that he becomes pure only if the kohen pronounces him fit for purification, not when the symptoms disappear. The second pasuk mentions that the kohen makes "a house call" to do so. The second explanation, based on Torat Kohanim, is that the stress that the metzora is brought to the kohen teaches that he is forced to go immediately to the kohen even if he prefers not to.
Besides answering the technical question, the Ramban’s explanations provide an educational/ psychological framework to understand the purification process from the metzora’s viewpoint. The metzora was afflicted by an apparently physical ailment. Instead of receiving a medical solution to the problem, a religious functionary condemned him to solitude and introspection on the spiritual cause of the ailment. That which we see as the only acceptable remedy to the root cause of the problem can seem to the metzora as the kohen’s shirking his leadership responsibilities and condemning the helpless. Therefore, the Torah ensures that it is a kohen who not only sends him away but also goes out to await the time that the metzora can be returned. He will be the one to welcome the metzora back to participate in society at the appointed time and in the correct manner.
The second approach is centered on a more complex psychological scenario. The metzora, who is condemned to live apart from society, can react in different ways. One is to give up on the connection with society. "If they don’t want me, I don’t want them." Another unfortunate, possible response is the fear of further rejection. "What if I call for a kohen and he declares that I am still not ready?" To distance the metzora from such reactions, the Torah decrees that when others feel the metzora is ready, he is required to go to the kohen and jump back into things. Whether or not he is ready to admit that he needs to be mainstreamed back into society or has the confidence, the kohen is to interpret the Divine signs that manifest themselves in the metzora’s physical state.
Return is not easy. However, there is a time for and a manner in which the path back home should be embarked upon.