Why Moses called the prophetic animals unclean

Hence, if I have admired anything else in Moses, I will declare this too worthy of admiration. He understood the different natures of animals, and, whether he learned from God about them and about the demons akin to each animal, or found it out himself as he rose by wisdom, in his ordinance concerning animals he said that all those reckoned prophetic by the Egyptians and the rest of mankind are unclean, and that, in general, those not of this kind are clean (Leviticus 11:1–47; Deuteronomy 14:3–20). Among the unclean in Moses are the wolf, the fox and the serpent, the eagle, the hawk and the like (Leviticus 11:13–19, 27, 42; Deuteronomy 14:12–18). And, in general, not only in the Law but also in the Prophets you would find these animals taken as examples of the very worst things, and you would never find a wolf or a fox named in connection with anything good.

It seems, then, that there is a certain fellowship between each kind of demon and each kind of animal. And just as among men some are stronger than others, not necessarily because of their character, in the same way some demons may be more powerful than others in morally indifferent matters. Some of them use these animals to deceive men, according to the will of the one who in our teaching is called “the ruler of this age” (John 12:31; 1 Corinthians 2:6), while others give their forewarnings through another kind. And see how foul the demons are, so that even weasels are used by some to reveal the future.

And you, judge for yourself which is better to accept: that the God over all and His Son move birds and the other animals to divination; or that those who move such animals, and not men, though men are present, are wicked demons, and, as our sacred writings have named them, “unclean” (Matthew 10:1).