GEN1232 One [should not] associate[] himself with an evil person. … the righteous detest the wicked, the pasuk says Psalms 15:4, “A despicable person is detested in his eyes.”  Our Sages, z”l, said concerning this Baba Kama 92b, “Not for naught does the starling mingle with the raven, but because it is of the same species.” [I.e., the starling, by mingling with the not-kosher raven, shows that it too is not kosher] and [ibid.] “Every bird dwells with its kind, and a human, with one who is like him.” Moreover, they said Megilah 28a, “It is forbidden to look at the likeness of an evil person, as the pasuk says Kings 2 3:14, “Were it not for my respect in the presence of Yehoshafat, king of Yehudah, I would not look at you nor see you”; and [ibid.], “Who ever looks at the likeness of a wicked person, his eyesight dims as he ages, as the pasuk says [this verse].   – [this occurred] as a result of his looking upon the form of Esav, even though he was not aware of Esav’s activities, since Esav concealed his deeds, as the pasuk says Isaiah 29:15, “Their deeds are [performed] in darkness.”  … many pathways toward death await one who associates himself with an evil person.   (See also, this cite, comment at 27:21)   GATES 383-5.