To Julian of Cos, on the Two Natures in Christ

Leo, bishop of the city of Rome, to his dearly loved brother Julian the bishop. [a]

By the hands of our brothers, whom we have sent from the city on behalf of the faith, we have sent our brother Flavian a very full refutation of Eutyches’s extravagant heresy. Yet we have received, through our son Basil, your letter, beloved, which gave us much pleasure by the fervor of its catholic spirit. So we have added this page too, which agrees with the other document, so that you may offer a united and vigorous resistance to those who seek to corrupt the gospel of Christ. For the wisdom and the teaching of the Holy Spirit are one and the same in you as in us, and whoever does not receive it is not a member of Christ’s body, and cannot glory in that Head in whom he denies that his own nature is present. What does it profit that most foolish old man to mangle, under the name of the Nestorian heresy, the belief of those whose most devout faith he cannot tear to pieces? For he declares that the only Son of God was born of the blessed Virgin’s womb in such a way that he wore the appearance of a human body without the reality of human flesh being united to the Word. In this he departs as far from the right path as Nestorius did in separating the Godhead of the Word from the substance of the manhood he assumed. Who does not see what monstrous opinions spring from this prodigious falsehood? For whoever denies the true manhood of Jesus Christ must be filled with many blasphemies: Apollinaris claims him as his own, Valentinus seizes on him, or Mani holds him fast, and none of these believed that there was true human flesh in Christ. But surely, if that is not accepted, it is denied not only that he who was in the form of God, yet abode in the form of a slave, was born man according to the flesh and a reasoning soul, but also that he was crucified, dead and buried, that on the third day he rose again, and that, seated at the right hand of the Father, he will come to judge the living and the dead in the very body in which he himself was judged. For these pledges of our redemption are made void if Christ is not believed to have the true and whole nature of true manhood. [b]

Or, because the signs of his Godhead were beyond doubt, is the proof that he had a human body to be counted false? Are the signs of both natures, then, to be accepted as proving him the Creator, but not accepted for the salvation of the creature? No! For the flesh did not lessen what belongs to his Godhead, nor did the Godhead destroy what belongs to his flesh. For he is at once eternal from his Father and temporal from his mother: beyond all harm in his own strength, able to suffer in our weakness. In the Godhead of the Trinity he is of one and the same substance with the Father and the Holy Spirit; but in taking manhood on himself, he is not of one substance but of one and the same person. So he was at once rich in poverty, almighty in submission, beyond suffering in his punishment, immortal in death. For the Word was not turned, in any part of itself, either into flesh or into soul, since the absolute and unchangeable nature of the Godhead is always entire in its essence, receiving no loss and no increase. It so blessed the nature it had assumed that this nature remained forever glorified in the person of the one who glorified it. But why should it seem unfitting or impossible that the Word and flesh and soul should be one Jesus Christ, and that the Son of God and the Son of Man should be one, if flesh and soul, which are of different natures, make one person even without the incarnation of the Word? For it is much easier for the power of the Godhead to bring about this union of himself and man than for the weakness of manhood to bring it about by itself in its own substance. [e]

So neither was the Word changed into flesh, nor the flesh into the Word. Both remain in one, and one is in both, not divided by their difference and not confused by mixing. He is not one from his Father and another from his mother, but the same: in one way from his Father before every beginning, and in another from his mother at the end of the ages. So he was the “mediator between God and men, the man Christ Jesus,” in whom dwelt “the fullness of the Godhead bodily.” For it was the assumed nature, not the assuming nature, that was raised up, because God “exalted him and gave him the name which is above every name, that in the name of Jesus every knee should bow, of things in heaven and things on earth and things under the earth, and that every tongue should confess that Jesus Christ the Lord is in the glory of God the Father.”

As for what Eutyches dared to say before the court of bishops, “that before the incarnation there were two natures in Christ, but after the incarnation one,” the judges ought to have pressed him with repeated and searching questions to give an account of this statement, so that it would not be passed over as something trivial, since it plainly flowed from the same source as his other poisonous opinions. For I think that in saying this he was convinced that the soul which the Savior assumed had lived in heaven before he was born of the Virgin Mary, and that the Word joined it to himself in the womb. But this is intolerable to catholic minds and ears. For the Lord who came down from heaven brought with him nothing that belonged to our condition: he did not receive a soul that had existed before, nor flesh that was not from his mother’s body. Beyond doubt, our nature was not assumed in such a way that it was first created and then assumed; it was created by the very act of being assumed. So what was rightly condemned in Origen must be punished in Eutyches too, unless he chooses to give up his opinion: that is, the assertion that souls had not only a life but also different actions before they were placed in human bodies. [i]

The Lord’s birth according to the flesh has certain features in which it goes beyond the ordinary beginnings of human life. He alone was conceived and born of a pure virgin without the desire of the flesh, and he was brought forth from his mother’s womb in such a way that her fruitfulness bore him without loss of her virginity. Yet his flesh was not of another nature than ours, nor was his soul breathed into him from another source than that of all other men. It excelled others not by a difference of kind but by superiority of power. For he had no opposition in his flesh, nor did the strife of desires give rise to a conflict of wills. His bodily senses were active without the law of sin, and the reality of his emotions, being under the control of his Godhead and his mind, was neither assaulted by temptations nor gave way to harmful influences. But true man was united to God, not brought down from heaven as to a soul that already existed, nor created out of nothing as to the flesh. That manhood bore the same person in the Godhead of the Word, and possessed a nature in common with us in its body and soul. For he would not be “the mediator between God and man” unless God and man had existed together in both natures, forming one true person. The greatness of the subject urges us to a lengthy discussion, but with a man of your learning there is no need for such full treatises, especially since we have already sent our brother Flavian, by our delegates, a sufficient letter to strengthen the minds not only of priests but also of the laity. We believe the mercy of God will see to it that, without the loss of a single soul, the sound may be defended against the devil’s wiles and the wounded healed. Dated the 13th of June, in the consulship of the illustrious Asturius and Protogenes, in the year 449.