The seventh of the anathemas against Origen:
IF anyone shall say that Christ, of whom it is said that he appeared in the form of God, and that he was united before all time with God the Word, and humbled himself in these last days even to humanity, had (according to their expression) pity upon the divers falls which had appeared in the spirits united in the same unity (of which he himself is part), and that to restore them he passed through divers classes, had different bodies and different names, became all to all, an Angel among Angels, a Power among Powers, has clothed I himself in the different classes of reasonable beings with a form corresponding to that class, and finally has taken flesh and blood like ours and is become man for men; [if anyone says all this] and does not profess that God the Word humbled himself and became man: let him be anathema.
Now, before you point out that these anathemas do not officially appear in the main body of the actual Synod, look more closely at the reasoning of the above anathema, and notice that the anathema is based on the Incarnation itself (Chalecedonian theology). This is all straight out of the Christology of the Church, as expressed by Chalcedon all the way through the Seventh Council: redemption is only possible through the Incarnation. It is only through the veil of His flesh that salvation is possible. Satan does not have a human nature, and thus cannot be redeemed by the Incarnation.
The logic of this anathema is also linked to the ecumenical denunciation of Origen's universalism and pre-existence of souls by the 5th Synod: if Origen's doctrine of the pre-existence of souls were correct, the fall involved a fall from a higher to a lower mode of being - from a higher spiritual plane to a lower (for the demons), and from a higher to an even lower for humans (physicality). Thus, the Incarnation would be unnecessary to salvation, and repentance could be achieved apart from the God-Man.
