VIII. A protest against their faithlessness and inconsistency in this matter.
And so, as all these heresies have been destroyed, which through the holy devotion of the presiding Fathers have been cut off from the body of the Catholic unity, and which deserved to be exiles from Christ, because they have made the Incarnation of the Word, which is the one salvation of those who believe aright, a stone of offense and a stumbling-block to themselves, I am surprised that you, beloved, have any difficulty in discerning the light of the Truth. And since it has been made clear by numerous explanations that the Christian Faith was right in condemning both Nestorius and Eutyches with Dioscorus, and that a man cannot be called a Christian who gives his assent to the blasphemous opinion of either the one or the other, I am grieved that you are, as I hear, doing despite to the teaching of the Gospel and the Apostles by stirring up the various bodies of citizens with seditions, by disturbing the churches, and by inflicting not only insults, but even death, upon priests and bishops, so that you lose sight of your resolves and profession through your fury and cruelty.
Where is your rule of meekness and quietness? Where is the long-suffering of patience? Where the tranquillity of peace? Where the firm foundation of love and courage of endurance? What evil persuasion has carried you off, what persecution has separated you from the gospel of Christ? Or what strange craftiness of the Deceiver has shown itself that, forgetting the prophets and apostles, forgetting the health-giving creed and confession which you pronounced before many witnesses when you received the sacrament of baptism you should give yourselves up to the Devil's deceits?
What effect would “the Claws” and other cruel tortures have had on you if the empty comments of heretics have had so much weight in taking the purity of your faith by storm? You think you are acting for the Faith and yet you go against the Faith. You arm yourselves in the name of the Church and yet fight against the Church. Is this what you have learned from prophets, evangelists, and apostles? To deny the true flesh of Christ, to subject the very essence of the Word to suffering and death, to make our nature different from His who repaired it, and to reckon all that the cross uplifted, that the spear pierced, that the stone on the tomb received and gave back, to be only the work of Divine power, and not also of human humility?
It is in reference to this humility that the Apostle says, “For I do not blush for the Gospel,” inasmuch as he knew what a slur was cast upon Christians by their enemies. And, therefore, the Lord also made proclamation, saying: “he that shall confess Me before men him will I also confess before My Father.” For these will not be worthy of the Son and the Father's acknowledgment in whom the flesh of Christ awakens no respect: and they will prove themselves to have gained no virtue from the sign of the cross who blush to avow with their lips what they have consented to bear upon their brows.
Source: Letters (New Advent)