"And after six days Jesus taketh Peter, James, and John his brother, and bringeth them up into an high mountain apart, And was transfigured before them: and his face did shine as the sun, and his raiment was white as the light. And, behold, there appeared unto them Moses and Elias talking with him. Then answered Peter, and said unto Jesus, Lord, it is good for us to be here: if thou wilt, let us make here three tabernacles; one for thee, and one for Moses, and one for Elias. While he yet spake, behold, a bright cloud overshadowed them: and behold a voice out of the cloud, which said, This is my beloved Son, in whom I am well pleased; hear ye him." -Matthew 17:1-5
The transfiguration on the mount shows something that is often missed. The scripture is used to show Moses and Elijah as being the two witnesses of Revelation, but (while I don't dispute that view) Moses and Elijah symbolize the two main components of the Old Testament: the Law and the Prophets. Jesus spoke regarding the law and the prophets often as accompanying each other, and rightfully so, for both the law and the prophets pointed to Christ. It's written, "For all the prophets and the law prophesied until John," and again. "The law and the prophets were until John..." also, "On these two commandments hang all the law and the prophets" and other scriptures can be employed to witness that the law and the prophets were the main two components of the old covenant which pointed to Christ that would come as the fulfiller of each. But in trying to make an everlasting standard of the law and the prophets (by making tabernacles of remembrance for the three), the voice from the cloud pointed to adherence to Christ, as some things are done away in Him, and all things written are to be fulfilled by Him. This is why Christ stated in the scriptures of Matthew, "Think not that I am come to destroy the law, or the prophets: I am not come to destroy, but to fulfil. For verily I say unto you, Till heaven and earth pass, one jot or one tittle shall in no wise pass from the law, till all be fulfilled." and further clarified in the scriptures of Luke, "...These are the words which I spake unto you, while I was yet with you, that all things must be fulfilled, which were written in the law of Moses, and in the prophets, and in the psalms, CONCERNING ME." The law and the Prophets pointed forward to the Christ to come, and the Apostles pointed us back to the one who had died, rose, and would return. All things were made for Him! The schoolmaster was only meant to guide us to Christ, not be an accompanying measure of holiness along side faith in Christ, for by the law can no man be saved, and, just as walking with mixed garments, no man can walk both under the law and in the Spirit. It is Christ to which we should hear. Cyril of Alexandria wrote likewise concerning the transfiguration: "But besides the wonderful and ineffable sight of Christ’s glory, something else was done, useful and necessary for the confirmation of their faith in Him: and not for the disciples only, but even for us too. For a voice was given forth from the cloud above, as from God the Father, saying: “This is My beloved Son, hear Him. And when there was the voice,” it says, “Jesus was found alone.” What then will he who is disputatious and disobedient, and whose heart is incurable, say to these things? Lo! Moses is there, and does the Father command the holy apostles to hear him? Had it been His will that they should follow the commandments of Moses, He would have said, I suppose, Obey Moses; keep the law. But this was not what God the Father here said, but in the presence of Moses and the prophets, He commands them rather to hear Him. And that the truth might not be subverted by any, affirming that the Father rather bade them hear Moses, and not Christ the Saviour of us all, the Evangelist has clearly marked it, saying, “When there was the voice, Jesus was found alone.” When therefore God the Father, from the cloud overhead, commanded the holy apostles, saying, “Hear Him,” Moses was far away, and Elijah too was no longer nigh; but Christ was there alone. Him therefore He commanded them to obey. For He also is the end of the law and the prophets: for which reason He cried aloud to the multitudes of the Jews: “If ye had believed Moses, ye would have believed Me also: for he wrote of Me.” But as they persevered even unto the end in despising the commandment given by most wise Moses, and in rejecting the word of the holy prophets, they have justly been alienated and expelled from those blessings that were promised to their fathers. For “obedience is better than sacrifices, and to hearken than the fat of rams,” as the Scripture saith. And thus much then of the Jews: but upon us who have acknowledged the revelation, all these blessings have necessarily been bestowed, by means of and as the gift of the same Christ..." Leo the Great wrote: "For the apostles, who really needed to be strengthened in faith and initiated into a knowledge of every thing, from that miracle comes another lesson. In fact, Moses and Elijah — the Law and the Prophets — appeared hobnobbing with the Lord. This happened so as to perfectly accomplish through the presence of five people what is written: “Every word is confirmed, if delivered in the presence of two or three witnesses “(Deut. 19.15 Mt 18:16). To proclaim it, the two trumpets of the Old and New Testament resound in full agreement and everything needed to witness to it in ancient times is reunited with the teaching of the Gospel! The pages of both of Testaments, in fact, confirm each other, and he who was promised by the ancient symbols under the veil of mystery is now manifested by the blaze of his glory. It is He – as St. John would say: “The law was given by Moses, but grace and truth came to us through Jesus Christ” (Jn 1.17), in whom has been fulfilled not only the promises by the prophetic figures, but also the meaning of the precepts of the Law , because, by his presence, he teaches the truth of prophecy, and by His grace, makes possible the practice of the commandments.
Inspired by the revelation of the mysteries and taken up by contempt and disgust for earthly things, the apostle Peter was in ecstasy at the desire of eternal things, and, filled with the joy of all this vision, wanted to live with Jesus, there where His glory was manifested. That’s why he said: “Lord, it is good for us to be here if you want, we here three tabernacles, one for you, one for Moses and one for Elijah” (Matt. 17.4). But the Lord did not reply to this suggestion, certainly not to show that this desire was bad, but to signify that it was out of place. The world could not be saved without the death of Christ, you see. Thus, the Lord’s example calls on the faith of believers to understand that, no doubt against the promise of happiness, we must nevertheless, in the trials of this life, ask for patience before glory; the happiness of the kingdom can not, in fact, precede the time of suffering.
And so, while he was still speaking, a bright cloud overshadowed them and a voice from the cloud said, “This is my beloved Son in whom I am well pleased, listen to him” (Mt 17.5). The Father, no doubt, was present in the Son, and in that light that the Lord had measured out to the disciples, the essence of Him who generates is not separated from the generated Only Begotten, but to highlight the proper characteristics of each Person, the Voice coming out of the cloud announced the Father to human ears, just as the splendor coming forth from the body revealed the Son to human eyes. When they heard the voice, the disciples fell face down, very frightened, trembling not only before the majesty of the Father, but also before that of the Son: through the motion of a deeper understanding in fact, they understood that the Divinity of both was unique. And since there was no hesitation in faith there was discretion in fear. That divine testimony was so wide and varied, and the power of words made them realize more than the sound of the voice can express. In fact, when the Father says: “This is my beloved Son, in whom I am well pleased, listen to him,” one should not perhaps understand clearly: “This is my Son,” for which to be “from me” and to be “with me” is a reality that is not time-bound? Neither is He who Generates prior to Him who is Generated; nor is the one Generated posterior to the One who Generates.”
“This is my Son,” who does not take away from me my Divinity, nor does He divide power, nor eternity.
“This is my Son,” — He is not adopted, but really, not indeed created, but generated from me, no different in nature and made similar unto me. But He is of my very being and was born equal to me.
“This is my Son”, through whom all things were made and without whom nothing was made” (Jn 1.3): all that I do he also does it (Jn 5.19) and as I work, he works with me without a difference. In fact, the Father is in the Son just as the Son is in the Father (Jn 10:38), and our unity never separates. And though I the one who generates is different from the one generated, it is not however allowed to have a different opinion about him that one can have of me.
“This is my Son,” who did not count equality of with me something to be grasped at (Phil. 2.6), or to usurp, appropriating it for himself; rather, while remaining in the condition of his glory, he, to complete the design of the restoration of mankind, brought to humility the immutable Divinity to the condition of a servant.
To Him, therefore, in whom is all my pleasure, and whose teachings I manifest, whose humility glorifies me — listen to him without hesitation, for he is truth and life (Jn 14.6), he is my strength and my wisdom (1 Cor 1.24).
“Listen to Him,” he whom the Mysteries of the Law announced; whom the voice of the prophets sang about.
“Listen to Him,” he who has redeemed the world with his blood, who has chained the devil and who has snatched away the spoil(Matt. 12:29), who has torn up the document of our debts (Col. 2:14), and the covenant that oppressed us.
“Listen to Him,” he who opens the way to heaven, and with the agony of the cross, prepares there the stairs leading up to the Kingdom. Why are you afraid of being redeemed? Why are you afraid of being dissolved from your chains? Let it happen that, what I wish, Christ also wills. Throw away that carnal fear and arm yourself with the constancy that inspires faith. It is unworthy of you, in fact, to be afraid of what in the Lord’s passion you would not fear in death, with his help.
These things, beloved, were said not only for the good of those who heard it then with their ears. Rather, in the person of the three apostles, it is the whole Church which learns what they saw with their eyes and perceived with their ears. May it strengthen the faith of all according to the preaching of the holy Gospel, and let no one ashamed of the cross of Christ, through which the world has been redeemed. Consequently, let no one be afraid of suffering for righteousness (1P 3.14), nor hesitate to receive the promised reward, because it is through labor that we are led rest, and life through death. In fact, he took upon himself the weakness of our own lowliness; and — if we stay with Him (Jn 15.9) in his confession and his love — we are winners of what he has won and will receive what he promised." Augustine also writes: "We heard, as the Gospel was read, the story of the great vision in which the Lord showed himself to three disciples, Peter and John and James. “His face shone like the sun” – this means the splendor of the Gospel. “His clothes became as white as snow” – that is to say, the purification of the Church, about which the Prophet said: “Though your sins be red like crimson, I will make them white as snow” (Isaiah 1.18 ). Moses and Elijah were talking with him, for the grace of the Gospel receives the witness of the Law and the Prophets. For Moses, one understoods the Law; for Elijah, the Prophets are meant. Peter suggested that they build three tents, one for Moses and one for Elijah, one for Christ. He liked the solitude of the mountain; he was bored of the tumult of human affairs. But why did he wish to make three tents? Did he not know that the Law, the Prophets and the Gospel come from the same origin? In fact he was corrected by the cloud. “As he said this a bright cloud overshadowed them.” So the cloud made one tent, so why would you want three? And a voice from the cloud said, “This is my beloved Son: heed him” (Mt17.1 to 8). Elijah speaks, but “listen to him.” Moses speaks, “but listen to him.” Prophets speak, the Law speaks, but “heed him”, the voice of the Law and the tongue of the Prophets. It was he who spoke through them, and then he spoke by himself, when he deigned to be manifested. “Hear him,” listen to him. When the Gospel spoke, know who was the voice of the cloud; from there, it came to us. We hear him; do what he tells us. Let us hope what he promises." It is made clear in the transfiguration on the Mount that the Law and the Prophets are replaced by faith in Christ (even once they opened their eyes there was none left except Christ alone), but even till this day men have made tabernacles to Moses and to Elijah.
"But now the righteousness of God without the law is manifested, being witnessed by the law and the prophets;" -Paul