Chasidut do Negaim 2:7

We learned "a person sees all defects, except (chutz) their own defects" (M. Nega'im 2:5) and the holy Ba'al Shem Tov explained that "a person sees all defects outside (chutz)" - what they see is a continuation of that person's defects, as our sages say "he disqualifies others with his own flaw."