Nicene and Post-Nicene Fathers, Ser. II, Vol. XI:
The Works of John Cassian.: Chapter V. The answer on the heresy described above.

Chapter V.

The answer on the heresy described above.

Isaac: We need not be surprised that a really simple man who had never received any instruction on the substance and nature of the Godhead could still be entangled and deceived by an error of simplicity and the habit of a longstanding mistake, and (to speak more truly) continue in the original error which is brought about, not as you suppose by a new illusion of the demons, but by the ignorance of the ancient heathen world, while in accordance with the custom of that erroneous notion, by which they used to worship devils formed in the figure of men, they even now think that the incomprehensible and ineffable glory of the true Deity should be worshipped under the limitations of some figure, as they believe that they can grasp and hold nothing if they have not some image set before them, which they can continually address while they are at their devotions, and which they can carry about in their mind and have always fixed before their eyes. And against this mistake of theirs this text may be used: “And they changed the glory of the incorruptible God into the likeness of the image of corruptible man.” 1665 Jeremiah also says: “My people have changed their glory for an idol. 1666 Which error although by this its origin, of which we have spoken, it is engrained in the notions of some, yet none the less is it contracted in the hearts also of those who have never been stained with the superstition of the heathen world, under the colour of this passage where it is said “Let us make man after our image and our likeness,” 1667 ignorance and simplicity being its authors, so that actually there has arisen owing to this hateful interpretation a heresy called that of the Anthropomorphites, which maintains with obstinate perverseness that the infinite and simple substance of the Godhead is fashioned in our lineaments and human configuration. Which however any one who has been taught the Catholic doctrine will abhor as heathenish blasphemy, and so will arrive at that perfectly pure condition in prayer which will not only not connect with its prayers any figure of the Godhead or bodily lineaments (which it is a sin even to speak of), but will not even allow in itself even the memory of a name, or the appearance of an action, or an outline of any character.

Footnotes

Rom. i. 23.

Jer. ii. 11.

Gen. i. 26.