This week's parsha speaks about the laws of meztora. Tzora'as was a discoloration of the skin caused by loshon hora. If someone had it, only a kohein, a descendant of of Aharon, was allowed to say whether the individual was tomei or tohor (impure or okay). If the kohein does not know all the different types of tzora'as, he needs a chacham (expert) who knows the laws to look at it. The chacham tells the kohein to announce whether the Jew is tahor or whether he needs to be quarantined, etc. If the kohein relies on the chacham to diagnose, why doesn't the chacham announce if someone is tomei or tohor, why must the kohein be the one to annnounce it and give the virdct
The Rebbe explains that tzora'as is very severe, because once the person is tomei, he was almost excommunicated. He was excluded from all three camps of Bnei Yisroel and couldn't even be near anyone else who had tzora'as. This is because the person spoke loshon horah and caused a separation between family members or between friends. To give someone such a severe punishment can only be done by someone who has Ahavas Yisroel. Aharon Hakohein was known to have Ahavas Yisroel, and the kohanim, his descendants, bless Bnei Yisroel “with love”as it says in Birchas Kohanim. Therefore, only someone who has the innate characteristic of love can be the one to determine whether someone has tzora'as.
Once the kohein says that someone is tomei or must be quarantined, that same kohein must be the one to proclaim him tohor. The kohein will be there at the earliest time possible to pronounce him tohor. Therefore, even if the kohein relies on the chacham, he will ask and re-ask the chacham before determining a negative (tomei) outcome. That is why the responsibility was given only to the children of Aharon. A person can be the wisest of all, and know the laws better than anyone else, but if he tells another Jew that he doesn't belong in the Jewish community and the power to make such a decision wasn't given to him, only to a kohein, he is speaking against another Jew and deserves to be afflicted with tzora'as. So what is his cure? He must sit alone away from everyone else and begin looking at other Jews with a good eye and get used to seeing others in a positive way and not harm other Jews with his loshon harah, and with that teshuva he will be cured. True ahavas yisroel with ahavas chinom – loving other Jews unconditionally will nullify the golus which is called tzora'as and automatically the complete redemption will come though Moshiach.
Likutei Sichos, Vol. 27