So great is the divergence between the doctrines. These men have now done their best to outdo Apollinarius, Arius and Eunomius, in their impiety and have now endeavoured to plant anew the heresy sown of old by Valentinus and Bardesanes, and afterwards uprooted by most excellent husbandmen. Like Valentinus and Bardesanes they have denied that the body of our Lord was assumed of our nature. But the Church, following the footprints of the Apostles, contemplates in the Lord Christ both perfect Godhead and perfect manhood. For just as He took a body, not that He needed a body, but by its means to give immortality to all bodies; so too He took a soul, the guide of the body, that every soul by its means might share His immutability. For even if souls are immortal, they are not however immutable; for they undergo many and frequent changes, as they experience pleasure, now from one object, and now from another. Whence it comes about that we err when we are changed and are inclined to what is worse. But after the resurrection our bodies enjoy immortality and incorruptibility, and our souls impassibility and immutability. For this reason the only begotten Son of God took both a body and a soul, preserved them free from all blame, and offered the sacrifice for the race. And this is why He is called our high priest; and He is named high priest not as God but as man. He makes the offering as man, and accepts the sacrifice with the Father and the Holy Spirit as God. If only Adam's body had sinned, it alone should have benefited by the cure. But since the soul not only shared in the sin but was first in the sin, for first the thought forms an image of the sin and then carries it out by means of the body, it was just, I ween, that the soul too should be healed. But it is perhaps superfluous to demonstrate these points by reasoning, when the divine Scripture clearly proclaims them. This doctrine is distinctly taught by the holy David and the very divine Peter, the one foretelling from distant ages, and the other interpreting his prediction. The words of the first of the apostles are “David therefore being a prophet, and knowing that God had sworn with an oath to him, that of the fruit of his loins, according to the flesh, He would raise up Christ to sit on his throne; he seeing this before spoke of the resurrection of Christ that His soul was not left in hell neither His flesh did see corruption.”
Now he has given us much instruction on the same point in these few words. First he states that the assumed nature derives its descent from the loins of David; secondly that He took not a body only, but also an immortal soul, and thirdly that He delivered body and soul to death, and, after taking them again, raised them as He would. His own words are “Destroy this temple and in three days I will raise it up.” But we have learned that the divine nature is immortal. What suffered was the passible, and the impassible remained impassible. For God the Word was made man not to render the impassible nature passible, but on the passible nature, by means of the Passion, to bestow the boon of impassibility. And the Lord Himself in the holy Gospels at one time says “I have power to lay down my life and I have power to take it again, no man takes it from me but I lay it down of myself;” “That I may take it again.” And again “Therefore does my Father love me because I lay down my life for the sheep,” and again “Now is my soul troubled” “my soul is exceeding sorrowful even unto death” and of His body He says “The bread that I will give is my flesh which I will give for the life of the world,” and when He delivered the divine mysteries and broke the symbol and distributed it, He added “This is my body which is being broken for you for the remission of sins,” and again “This is my blood which is shed for many for the remission of sins,” and again “Except you eat the flesh of the Son of Man and drink His blood you have no life in you” and “Whosoever eats my flesh and drinks my blood has eternal life” “in himself” he adds. Innumerable passages of the same character may be quoted, both in the old Testament and the new, pointing out the assumption both of the body and of the soul, and that they are descended from Abraham and David. Joseph of Arimathea when he came to Pilate begged the body of Jesus, and the fourfold authority of the holy Gospels tells us how he received the body, wrapped it in the linen cloth, and committed it to the tomb. I do, indeed, sorrow and lament that I am compelled by the attacks of error to adduce against men supposed to be of one and the same faith with myself the arguments which I have already urged against the victims of the plague of Marcion—of whom, by God's grace, I have converted more than ten thousand, and brought them to Holy Baptism. What child of the church ever had any doubts on these points? Who has not cited this teaching of the holy Fathers? The works of the great Basil are full of it; as well, as those of his fellow soldiers Gregory and Amphilochius, and of those who in the West have been illustrious teachers of grace, Damasus, bishop of great Rome, and Ambrose of Milan; and Cyprian of Carthage who for the sake of these doctrines won the martyr's crown. Five times was the famous Athanasius driven from his flock and compelled to dwell in exile; and in the cause of these doctrines strove too his master Alexander. Eustathius, Meletius, and Flavianus, luminaries of the East, and Ephraim, harp of the Spirit, who daily waters the people of Syria with the streams of grace; John and Atticus, loud heralds of the truth; and men of an earlier age than they, Ignatius, Polycarp, Irenæus, Justin, and Hippolytus, of whom the more part not only shine at the head of the company of bishops, but also adorn the martyr's band.
Source: Letters (New Advent)