Musar zu Könige II 3:31

The fourth section: One who attaches himself to an evildoer. It is not enough for him that he does not reprimand him with the rod of his mouth and surely distance him; but he rather brings him close like a friend. And it is stated (II Chronicles 20:37), “As you have made a partnership, etc., the Lord will break up your work.” Whereas the righteous are surely disgusted by the evildoer, as it is stated (Psalms 15:4), “A contemptible man is disgusting in his eyes.” And our Rabbis, may their memory be blessed, said (Bava Kamma 92b), “Not for naught did the starling go to the raven, but because it is its kind. And it stated, ‘All fowl will live with its kind, and men with those like him’ (Book of Ben Sira 13:17).” And they said (Megillah 28a), “It is prohibited for a person to gaze at the likeness of a wicked man, as it is stated (II Kings 3:14), ‘Were it not that I regard the presence of Jehoshaphat, the king of Judea, I would not look toward you, nor see you.’” And they [continued], “[Any one who gazes at the likeness of an evil man,] his eyes become dim [at the time of his old age], as it is stated (Genesis 27:1), ‘And it came to pass, that when Isaac was old, and his eyes were dim so that he could not see’ - because he gazed at the wicked Esau.” And we have already discussed very well that there are many ways of death found by one who attaches himself to an evildoer.

The Divine Presence does not rest upon any one unless there is joy (Shabbath 30b). And all of the prophets did not prophesy at such times as they desired, but they would prepare their minds and sit joyous and glad of heart and then prophesy, for Prophecy does not dwell where idleness or sadness is found, but only where joy is. Therefore, the pupils of the Prophets would place before them lyre, drum and harp and sought by their means the gift of Prophecy, as it is written "And it came to pass, when the minstrel played, that the hand of the Lord came upon him" (II Kings 3:15).

The righteous people reject the wicked, and our Sages, of blessed memory said, "Not for nothing did the starling follow the raven, but because it is of the same kind" (Baba Kamma 92b). And it is said, "Every fowl dwells near its kind and man near his equal" (Ben Sira 13:5). And they said, "It is forbidden to look at the form of a wicked man" (Megillah 28a), as it is said, "Were it not that I regard the presence of Jehoshaphat the king of Judah, I would not look toward thee, nor see thee" (II Kings 3:14). And everyone who looks at the form of a wicked man, his eyes grow dim in his old age, like Isaac, our father, whose eyes grew dim because he looked upon Esau, even though he did not know of Esau's evil deeds.