How the Back Parts of God Were Seen. The Faith of the Resurrection of Christ. The Catholic Church Only is the Place from Whence the Back Parts of God are Seen. The Back Parts of God Were Seen by the Israelites. It is a Rash Opinion to Think that God the Father Only Was Never Seen by the Fathers
Not unfitly is it commonly understood to be prefigured from the person of our Lord Jesus Christ, that His “back parts” are to be taken to be His flesh, in which He was born of the Virgin, and died, and rose again; whether they are called back parts on account of the posteriority of mortality, or because it was almost in the end of the world, that is, at a late period, that He deigned to take it: but that His “face” was that form of God, in which He “thought it not robbery to be equal with God,” which no one certainly can see and live; whether because after this life, in which we are absent from the Lord, and where the corruptible body presses down the soul, we shall see “face to face,” as the apostle says— (for it is said in the Psalms, of this life, “Verily every man living is altogether vanity;” and again, “For in Your sight shall no man living be justified;” and in this life also, according to John, “It does not yet appear what we shall be, but we know,” he says, “that when He shall appear, we shall be like Him, for we shall see Him as He is,” which he certainly intended to be understood as after this life, when we shall have paid the debt of death, and shall have received the promise of the resurrection);— or whether that even now, in whatever degree we spiritually understand the wisdom of God, by which all things were made, in that same degree we die to carnal affections, so that, considering this world dead to us, we also ourselves die to this world, and say what the apostle says, “The world is crucified unto me, and I unto the world.” For it was of this death that he also says, “Wherefore, if you be dead with Christ, why as though living in the world are you subject to ordinances?” Not therefore without cause will no one be able to see the “face,” that is, the manifestation itself of the wisdom of God, and live. For it is this very appearance, for the contemplation of which every one sighs who strives to love God with all his heart, and with all his soul, and with all his mind; to the contemplation of which, he who loves his neighbor, too, as himself builds up his neighbor also as far as he may; on which two commandments hang all the law and the prophets. And this is signified also in Moses himself. For when he had said, on account of the love of God with which he was specially inflamed, “If I have found grace in your sight, show me now Yourself plainly, that I may find grace in Your sight;” he immediately subjoined, on account of the love also of his neighbor, “And that I may know that this nation is Your people.” It is therefore that “appearance” which hurries away every rational soul with the desire of it, and the more ardently the more pure that soul is; and it is the more pure the more it rises to spiritual things; and it rises the more to spiritual things the more it dies to carnal things. But while we are absent from the Lord, and walk by faith, not by sight, we ought to see the “back parts” of Christ, that is His flesh, by that very faith, that is, standing on the solid foundation of faith, which the rock signifies, and beholding it from such a safe watchtower, namely in the Catholic Church, of which it is said, “And upon this rock I will build my Church.” For so much the more certainly we love that face of Christ, which we earnestly desire to see, as we recognize in His back parts how much first Christ loved us.
29. But in the flesh itself, the faith in His resurrection saves and justifies us. For, “If you shall believe,” he says, “in your heart, that God has raised Him from the dead, you shall be saved;” and again, “Who was delivered,” he says, “for our offenses, and was raised again for our justification.” So that the reward of our faith is the resurrection of the body of our Lord. For even His enemies believe that that flesh died on the cross of His passion, but they do not believe it to have risen again. Which we believing most firmly, gaze upon it as from the solidity of a rock: whence we wait with certain hope for the adoption, to wit, the redemption of our body; because we hope for that in the members of Christ, that is, in ourselves, which by a sound faith we acknowledge to be perfect in Him as in our Head. Thence it is that He would not have His back parts seen, unless as He passed by, that His resurrection may be believed. For that which is Pascha in Hebrew, is translated Passover. Whence John the Evangelist also says, “Before the feast of the Passover, when Jesus knew that His hour had come, that He should pass out of this world unto the Father.”
30. But they who believe this, but believe it not in the Catholic Church, but in some schism or in heresy, do not see the back parts of the Lord from “the place that is by Him.” For what does that mean which the Lord says, “Behold, there is a place by me, and you shall stand upon a rock?” What earthly place is “by” the Lord, unless that is “by Him” which touches Him spiritually? For what place is not “by” the Lord, who “reaches from one end to another mightily, and sweetly does order all things,” and of whom it is said, “Heaven is His throne, and earth is His footstool;” and who said, “Where is the house that you build unto me, and where is the place of my rest? For has not my hand made all those things?” But manifestly the Catholic Church itself is understood to be “the place by Him,” wherein one stands upon a rock, where he healthfully sees the “Pascha Domini,” that is, the “Passing by” of the Lord, and His back parts, that is, His body, who believes in His resurrection. “And you shall stand,” He says, “upon a rock while my glory passes by.” For in reality, immediately after the majesty of the Lord had passed by in the glorification of the Lord, in which He rose again and ascended to the Father, we stood firm upon the rock. And Peter himself then stood firm, so that he preached Him with confidence, whom, before he stood firm, he had thrice from fear denied; although, indeed, already before placed in predestination upon the watchtower of the rock, but with the hand of the Lord still held over him that he might not see. For he was to see His back parts, and the Lord had not yet “passed by,” namely, from death to life; He had not yet been glorified by the resurrection.
Source: On the Holy Trinity (New Advent)