Musar zu Divrej Hajamim II 20:37

And it is forbidden to make an association with an evildoer for matters of the world, as it is stated (II Chronicles 20:37), “As you have made an association with Ahaziah, the Lord will break up your work.” And it is [also] stated (Proverbs 3:31), “Do not envy a lawless man, or associate with any of his ways.” And our Rabbis, may their memory be blessed, said in Avot DeRabbi Natan (Avot DeRabbi Natan 9:4), “Do not befriend an evildoer even for the matter of a commandment.” And there are many paths of death found in the association with evildoers; and we have already spoken about this iniquity and the severity of its punishment.

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.

And it is forbidden to associate with a wicked man in business or social or community affairs, as it is said: "Because you have joined yourself with Ahaziah the Lord has made a breach in your works!" (II Chron. 20:37).