St. IGNATIUS -- Epistle to the Ephesians -- Beware of false teachers.

For some are in the habit of carrying about the name [of Jesus Christ] in wicked guile, while yet they practise things unworthy of God, whom ye must flee as ye would wild beasts. For they are ravening dogs, who bite secretly, against whom ye must be on your guard, inasmuch as they are men who can scarcely be cured. There is one Physician who is possessed both of flesh and spirit; both made and not made; God existing in flesh; true life in death; both of Mary and of God; first possible and then impossible, even Jesus Christ our Lord.

But some most worthless persons are in the habit of carrying about the name [of Jesus Christ] in wicked guile, while yet they practise things unworthy of God, and hold opinions contrary to the doctrine of Christ, to their own destruction, and that of those who give credit to them, whom you must avoid as ye would wild beasts.

For “the righteous man who avoids them is saved for ever; but the destruction of the ungodly is sudden, and a subject of rejoicing.” For “they are dumb dogs, that cannot bark,” raving mad, and biting secretly, against whom ye must be on your guard, since they labour under an incurable disease. But our Physician is the only true God, the unbegotten and unapproachable, the Lord of all, the Father and Begetter of the only-begotten Son. We have also as a Physician the Lord our God, Jesus the Christ, the only-begotten Son and Word, before time began, but who afterwards became also man, of Mary the virgin. For “the Word was made flesh.” Being incorporeal, He was in the body; being impassible, He was in a passible body; being immortal, He was in a mortal body; being life, He became subject to corruption, that He might free our souls from death and corruption, and heal them, and might restore them to health, when they were diseased with ungodliness and wicked lusts.