The second half of Chapter 13 of St John's Gospel foreshadows the two coming betrayals: by Judas and Peter.
The New Advent Bible page has the Greek, Knox translation English and Latin in parallel text form. You can listen to the Latin here and the Greek here.
Here is the Latin:
21 Cum hæc dixisset Jesus, turbatus est spiritu: et protestatus est, et dixit: Amen, amen dico vobis, quia unus ex vobis tradet me. 22 Aspiciebant ergo ad invicem discipuli, hæsitantes de quo diceret. 23 Erat ergo recumbens unus ex discipulis ejus in sinu Jesu, quem diligebat Jesus. 24 Innuit ergo huic Simon Petrus, et dixit ei: Quis est, de quo dicit? 25 Itaque cum recubuisset ille supra pectus Jesu, dicit ei: Domine, quis est? 26 Respondit Jesus: Ille est cui ego intinctum panem porrexero. Et cum intinxisset panem, dedit Judæ Simonis Iscariotæ. 27 Et post buccellam, introivit in eum Satanas. Et dixit ei Jesus: Quod facis, fac citius. 28 Hoc autem nemo scivit discumbentium ad quid dixerit ei. 29 Quidam enim putabant, quia loculos habebat Judas, quod dixisset ei Jesus: Eme ea quæ opus sunt nobis ad diem festum: aut egenis ut aliquid daret. 30 Cum ergo accepisset ille buccellam, exivit continuo. Erat autem nox.31 Cum ergo exisset, dixit Jesus: Nunc clarificatus est Filius hominis, et Deus clarificatus est in eo. 32 Si Deus clarificatus est in eo, et Deus clarificabit eum in semetipso: et continuo clarificabit eum. 33 Filioli, adhuc modicum vobiscum sum. Quæretis me; et sicut dixi Judæis, quo ego vado, vos non potestis venire: et vobis dico modo. 34 Mandatum novum do vobis: ut diligatis invicem: sicut dilexi vos, ut et vos diligatis invicem. 35 In hoc cognoscent omnes quia discipuli mei estis, si dilectionem habueritis ad invicem. 36 Dicit ei Simon Petrus: Domine, quo vadis? Respondit Jesus: Quo ego vado non potes me modo sequi: sequeris autem postea. 37 Dicit ei Petrus: Quare non possum te sequi modo? animam meam pro te ponam. 38 Respondit ei Jesus: Animam tuam pro me pones? amen, amen dico tibi: non cantabit gallus, donec ter me neges.
The Douay-Rheims version:
When Jesus had said these things, he was troubled in spirit; and he testified, and said: Amen, amen I say to you, one of you shall betray me.  The disciples therefore looked one upon another, doubting of whom he spoke.  Now there was leaning on Jesus' bosom one of his disciples, whom Jesus loved.  Simon Peter therefore beckoned to him, and said to him: Who is it of whom he speaketh?  He therefore, leaning on the breast of Jesus, saith to him: Lord, who is it?  Jesus answered: He it is to whom I shall reach bread dipped. And when he had dipped the bread, he gave it to Judas Iscariot, the son of Simon.  And after the morsel, Satan entered into him. And Jesus said to him: That which thou dost, do quickly.  Now no man at the table knew to what purpose he said this unto him.  For some thought, because Judas had the purse, that Jesus had said to him: Buy those things which we have need of for the festival day: or that he should give something to the poor.  He therefore having received the morsel, went out immediately. And it was night.  When he therefore was gone out, Jesus said: Now is the Son of man glorified, and God is glorified in him.  If God be glorified in him, God also will glorify him in himself; and immediately will he glorify him.  Little children, yet a little while I am with you. You shall seek me; and as I said to the Jews: Whither I go you cannot come; so I say to you now.  A new commandment I give unto you: That you love one another, as I have loved you, that you also love one another.  By this shall all men know that you are my disciples, if you have love one for another. Simon Peter saith to him: Lord, whither goest thou? Jesus answered: Whither I go, thou canst not follow me now; but thou shalt follow hereafter.  Peter saith to him: Why cannot I follow thee now? I will lay down my life for thee.  Jesus answered him: Wilt thou lay down thy life for me? Amen, amen I say to thee, the cock shall not crow, till thou deny me thrice.
The Catena Aurea comments on Jesus' distress at the prospect of losing one of his own :
CHRYS. Our Lord after His twofold promise of assistance to the Apostles in their future labors, remembers that the traitor is cut off from both, and is troubled at the thought: When Jesus had thus said, He was troubled in spirit, and testified, and said, Verily, verily, I say to you, that one of you shall betray Me.
AUG. This did not come into His mind then for the first time; but He was now about to make the traitor known, and single him out from the rest, and therefore was troubled in spirit. The traitor too was now just about to go forth to execute his purpose. He was troubled at the thought of His Passion being so near at hand, at the dangers to which His faithful followers would be brought at the hand of the traitor, which were even now impending over Him. Our Lord deigned to be troubled also, to show that false brethren cannot be cut off; even in the most urgent necessity, without the troubling of the Church. He was troubled not in flesh, but in spirit; for on occasion of scandals of this kind, the spirit is troubled, not perversely, but in love, lest in separating the tares, some of the wheat too be plucked up with them. But whether He was troubled by pity for perishing Judas, or, by the near approach of His own death, He was troubled not through weakness of mind, but power: He was not troubled because anything compelled Him, but He troubled Himself, as was said above. And in that He was troubled, He consoles the weak members of His body, i.e. His Church, that they may not think themselves reprobate, should they be troubled at the approach of death.
ORIGEN. His being troubled in spirit, was the human part, suffering under the excess of the spiritual. For if every Saint lives, acts, and suffers in the spirit, how much more is this true of Jesus, the Rewarder of Saints.
AUG. Away then with the reasonings of the Stoics, who deny that perturbation of mind can come upon a wise man; who, as they take vanity for truth, so make their healthy state of mind insensibility. It is good that the mind of the Christian may be perturbed, not by misery, but by pity. One of you, He said, i.e. one in respect of number, not of merit, in appearance not in virtue.
CHRYS. As He did not mention Him by name, all began to fear: Then the disciples looked one on another, doubting of whom He spoke; not conscious of any evil in themselves, and entrusting to Christ's words, more than to their own thoughts.
AUG. They had a devoted love for their Master but yet so that human weakness made them doubt of one another.
ORIGEN. They remembered too, that, as men, before they were matured, their minds were liable to change, so as to form wishes the very opposite to what they might have had before.
On Judas' departure, the die is cast:
ORIGEN. After the glory of His miracles, and His transfiguration, the next glorifying of the Son of man began, when Judas went out with Satan, who had entered into him; Therefore when he was gone out, Jesus said, Now is the Son of man glorified, and God is glorified in Him. For it is not the eternal only-begotten Word, but the glory of the Man born of the seed of David, which is here meant.
Christ at His death, in which He glorified God, having spoiled principalities and powers, made a show of them, openly triumphing over them (Col 2:15). And again, Made peace by the blood of His cross, to reconcile all things to Himself, whether they be things in earth, or things in heaven (Col 1:20). Thus the Son of man was glorified, and God glorified in Him; for Christ cannot be glorified, except the Father be glorified with Him. But whoever is glorified, is glorified by someone.
By whom then is the Son of man glorified? He tells you; If God be glorified in Him, God shall also glorify if Him in Himself, and shall straightway glorify Him.
CHRYS. i.e. by Himself, not by any other. And shall straightway glorify Him, i.e. not at any distant time, but immediately, while He is yet on the very cross shall His glory appear. For the sun was darkened, rocks were rent, and many bodies of those that slept arose. In this way He restores the drooping spirits of His disciples, and persuades them, instead of sorrowing, to rejoice.
AUG. Or thus: The unclean went out: the clean remained with their cleanser. Thus will it be when the tares are separated from the wheat; The righteous shall shine forth as the sale in the kingdom of their Father (Matt 13:43). Our Lord, foreseeing this, said, when Judas went out, as if the tares were now separated, and He left alone with the wheat, the holy Apostles.
Now is the Son of man glorified; as if to say, Behold what will take place at My glorifying, at which none of the wicked shall be present, none of the righteous shall perish. He does not say, Now is the glorifying of the Son of man signified; but, Now is the Son of man glorified; as it is not that rock signified Christ, or but, That Rock was Christ (1 Cor 10:4).
Scripture often speaks of the things signifying, as if they were the things signified. But the glorifying of the Son of man, is the glorifying of God in Him; as He adds, And God is glorified in Him, which He proceeds to explain; If God is glorified in Him - for He came not to do His own will, but the will of Him that sent Him - God shall also glorify Him in Himself, so that the human nature which was assumed by the eternal Word, shall also be endowed with eternity.
And shall straightway glorify Him. He predicts His own resurrection, which was to follow immediately, not at the end of the world, like ours. Thus it is; Now is the Son of man glorified; the now referring not to His approaching Passion, hut the resurrection which was immediately to follow it: as if that which was so very soon to be, had already taken place.
HILARY. That God is glorified in Him, refers to the glory of the body, which glory is the glory of God, in that the body borrows its glory from its association with the Divine nature because God is glorified in Him, therefore He will; glorify Him in Himself, in that He who reigns in the glory arising from the glory of God, He forthwith passes over into God's glory, leaving the dispensation of His manhood wholly to abide in God.
Nor is He silent as to the time And shall straightway glorify Him. This referring to the glory of His resurrection which was immediately to follow His passion, which He mentions as present, because Judas had now gone out to betray Him; whereas that God would glorify Him in Himself, He reserves for the future. The glory of God was strewn in Him by the miracle of the resurrection; but He will abide in the glory of God when He has left the dispensation of subjection.
The sense of these first words, Now is the Son of man glorified, is not doubtful: it is the glory of the flesh which is meant, not that of the Word But what means the next, And God is glorified in Him? The Son of man is not another Person from the Son of God for, the Word was made flesh (John 1:14). How is God glorified in this Son of man, who is the Son of God?
The next clause helps us; If God is glorified in Him, God also will glorify Him in Himself. A man is not glorified in himself, nor, on the other hand, does God who is glorified in man, because He receives glory, cease to be God. So the words, God is glorified in Him, either mean that Christ is glorified in the flesh, or that God is glorified in Christ. If God means Christ, it is Christ who is glorified in the flesh; if the Father, then it is the Sacrament of unity, the Father glorified in the Son. Again, God glorifies in Himself God glorified in the Son of man.
This overthrows the impious doctrine that Christ is not very God, in verity of nature. For how can that which God glorifies in Himself be out of Himself? He whom the Father glorifies must be confessed to be in His glory, and He who is glorified in the glory of the Father, must be understood to be in the same case with the Father.
ORIGEN. Or thus: The word glory is here used in a different sense from that which some Pagans attach to it, who defined glory to be the collected praises of the many. It is evident that glory in such a sense is a different thing from that mentioned in Exodus, where it is said, that the glory of the Lord filled the tabernacle (Exod 40:34), and that the face of Moses was glorified. The glory here mentioned is something visible, a certain divine appearance in the temple, and on Moses' face; but in a higher and more spiritual sense we are glorified, when with the eye of the understanding we penetrate into the things of God.
For the mind when it ascends above material things, and spiritually sees God, is defied: and of this spiritual glory, the visible glory on the face of Moses is a figure: for his mind it was that was defied by converse with God. But there is no comparison between the excellent glory of Christ, and the knowledge of Moses, whereby the face of his soul was glorified: for the whole of the Father's glory shines upon the Son, who is the brightness of His glory, and the express image of His Person (Heb 1:3). Yea, and from the light of this whole glory there go forth particular glories, throughout the whole rational creation; though none can take in the whole of the divine glory, except the Son.
But so far as the Son was known to the world, so far only was He glorified. And as yet He was not fully known. But afterward the Father spread the knowledge of Him over the whole world, and then was the Son of man glorified in those who knew Him. And of this glory He has made all who know Him partakers: as said the Apostle: We all, with open face beholding as in a glass the glory of the Lord, are changed into the same image, from glory to glory (2 Cor 3:18), i.e. from His glory receive glory.
When He was approaching then that dispensation, by which He was to become known to the world, and to be glorified in the glory of those who glorified Him, He says, Now is the Son of man glorified (Matt 11:27). And because no man knows the Father but the Son, and he to whomsoever the Son will reveal Him, and the Son by the dispensation was about to reveal the Father; for this reason He said, And God is glorified in Him. Or compare this with the text below: He that has seen Me, has seen the Father. The Father who begat the Word is seen in the Word, who is God, and the image of the invisible God. But the words may be taken in a larger sense. For as through some the name of God was blasphemed among the Gentiles, so through the saints whose good deeds are seen and acknowledged by the world, the name of the Father in heaven is magnified.
But in whom was He so glorified as in Jesus, Who did no sin, neither was guile found in His mouth? Such being the Son, He is glorified, and God is glorified in Him. And if God is glorified in Him, the Father returns Him more than He gave. For the glory of the Son of man, when the Father glorifies Him, far exceeds the Father's glory, when He is glorified in the Son: it being fit that the greater should return the greater glory. And as this, viz. the glorifying of the Son of man, was just about to be accomplished, our Lord adds, And will straightway glorify Him.
He reminds them of the law of love:
AUG. And now He teaches them how to fit themselves to follow. Him: A new commandment I give to you, that you love one another. But does not the old law say, you shall love your neighbor as yourself (Lev 19:18)? Why then does He call it a new commandment? Is it because it strips us of the old man, and puts on us the new? That it renews the hearer, or rather the doer of it? Love does do this; but it is that love which our Lord distinguishes from the carnal affection: As I have loved you, that you also love one another. Not the love with which men love one another, but that of the children of the Most High God, w ho would be brethren of His only-begotten Son, and therefore love one another with that love with which He loved them, and would lead them to the fulfillment of their desires.
CHRYS. Or, as I have loved you: for My love has not been the payment of something owing to you, but had its beginning on My side. And you ought in like manner to do one another good, though you may not owe it.
AUG. But; do not think that that greater commandment, viz. that we: should love the Lord our God, is passed by. For, if we understand the two precepts aright, each is implied in the other. He who loves God cannot despise His commandment that he should love his neighbor; and he who loves his neighbor in a heavenly spiritual way, in the neighbor loves God. That is the love which our Lord distinguishes from all human love, when He adds, As I have loved you, what did He, in loving us, love, but God in us; not who was in us, but so that He might be? Wherefore let each of us so love the other, as that by this working of love, we make each other the habitations of God.
CHRYS. Passing over the miracles, which they were to perform, He makes love: the distinguishing mark of His followers; By this shall all men know that you are My disciples' if you have love one to another. This it is that evidences the saint or the disciple, as He calls him.
AUG. As if He said, Other gifts are shared with you by those who are not mine; birth, life, sense, reason, and such good things as belong alike to man and brutes; nay, and tongues, sacraments, prophecy, knowledge, faith, bestowing of goods upon the poor,; giving the body to be burned: but forasmuch as they have not charity, they are tinkling cymbals, they are nothing: nothing profits them.
36. Simon Peter said to him, Lord, where do you go? Jesus answered him, Where I go you can not follow me now; but you shall follow me afterwards.
Yet there is still another betrayal to come:
CHRYS. Great is love, and stronger than fire; nothing can stop its course. Peter the most ardent of all, as soon as he hears our Lord say, Where I go you cannot follow Me now, asks, Lord, where do you go?
AUG. The disciple asks this, as if he were ready to follow. But our Lord saw his heart; Jesus answered him, Where I go, you cannot follow Me now; He checks his forwardness, but does not destroy his hope; nay, confirms it; But you shall follow Me afterwards. Why do you hasten, Peter? The Rock has not yet established you with His Spirit. Be not lifted up with presumptions, you cannot follow now; but be not cast down with despair, you shall follow Me afterwards.
CHRYS. Peter, on receiving this answer, does not check his desire, but hastily conceives favorable hopes from it, and having got rid of the fear of betraying our Lord, feels secure, and becomes himself the interrogator, while the rest are silent: Peter said to Him, Lord, why cannot I follow you now? I will lay down my life for your sake.
What say you, Peter? He has said, you can not, and you say, you can: wherefore you shall know by experience, that your love is nothing, unless you are enabled from above: Jesus answered him,
Will you lay down your life for my sake?
BEDE. Which sentence may be read in two ways: either as affirming, you shall lay down your life for My sake, but now through fear of the death of the body, you shall incur spiritual death: or as mocking; as if He said,
AUG. Will you do that for Me, which I have not done yet for you? Can you go before, who can not come after? Why presume you so? Hear what you are: Verily, verily, I say to you, The cock shall not crow, till you have denied Me thrice, you who promises Me your death, shall thrice deny your life. Peter knew his great desire, his strength he knew not: he boasted of his will, while he was yet weak; but the Physician saw his weakness.
Some who perversely favor Peter, excuse him, and say that he did not deny Christ, because when asked by the servant maid, he said he did not know Him, as the other Evangelist witness more expressly. As if to deny the man Christ, was not to deny Christ; yea, that in Christ, which He was made for our sakes, that that which He made us might not perish. By what is He the Head of the Church, but by His humanity? And how then is he in the body of Christ, who denies the man Christ? But why do I argue so long? Our Lord does not say, The cock shall not crow till you deny man, or the Son of man, but till you deny Me.
What is Me, but that which He was? So then whatever Peter denied, he denied Christ: it is impious to doubt it. Christ said so, and Christ said true: beyond a doubt, Peter denied Christ. Let us not, to defend Peter, accuse Christ. The frailty of Peter himself, acknowledged its sin, when he witnessed by his tears the evil he had done in denying Christ. Nor do we say this, because we have pleasure in blaming the first of the Apostles; but that we may take warning from him, not to be confident of our own strength.
BEDE. Nevertheless, should any one fall, let the example of Peter save him from despair, and teach him that he can without delay obtain pardon from God.
CHRYS. It is manifest that our Lord permitted Peter's fall. He might have recalled him to begin with, but as he persisted in his vehemence, though He did not drive him to a denial, He let him go without assistance, that He might learn his own weakness, and not fall into such sin again, when the superintendence of the world had come to him, but that remembering what had happened to him, he might know himself.
AUG. That took place in the soul of Peter, which he offered in the body; though differently from what he meant. For before the death and resurrection of our Lord, he both died by his denial, and lived again by his tears.
AUG. This speech, The cock shall not crow, occurs in all the Evangelists, but not at the same time in all. Matthew and Mark: introduce it after they have left the house, in which they were eating; Luke and John before. We may suppose either that the two former are recurring to what had passed, or the two latter anticipating what is coming. Or the great difference not only of the words, but of the subjects which precede the speech, and which excite Peter to the presumption of offering to die, for or with our Lord, may lead us to conclude that he made this offer three times, and that our Lord three times replied, Before the cock crows, you shall deny Me thrice.