Midrasch zu Mischlej 14:32

A parable, to what is the matter like? To a man in whom there was an evil spirit. All the deeds which he does, or all the words which he utters, does he speak by his own intention? Does he not act only according to the idea of the evil spirit, which (rules) over him? So (was it with) the serpent. All the deeds which it did, and all the words which it spake, it did not speak except by the intention of Sammael. Concerning him, the Scripture says, "The wicked is thrust down in his evil-doing" (Prov. 14:32).