"He Should Brought to Aharon the Priest" (12:2)

Kohanim (priest) are people of inherent who bless the Jewish people with love. Therefor, when it comes to declaring somebody with the severe condition of tzara'as, which requires total isolation from the Jewish camp, it is imperative that this harsh judgment be done out of love, so the Torah require it to be done by a priest.

From this we can learn a powerful lesson: that if one feels that another person has acted disgracefully and one wishes to chastise him, one must first examine one's own motives to see if one's desire to rebuke another is truly being out of love.

(Based on Likutei Sichos vol. 27, p. 88ff)