“For it was Moses who gave the Law and the Jews would therefore understand that he [The Lord Jesus Christ] had never neglected or scorned the Law as they suspected, and never broken it, but rather followed it and was opposed to all who set it aside. And Elijah was filled with zeal for the glory of God and if Christ really had been an anti-god calling himself God, making himself equal to the Father while not being what he said he was and not doing this legitimately, then he too would never have stood with him or been subject to Him. Apart from these things we have said so far, there is still something to speak of. What is it? Well, they came so that the disciples might learn that Christ has the power of life and death and rules over those who are above as well those who are below. For this reason he brings forward the one who was still living, and the one who was dead. And when they appeared they were not silent but spoke about the glory which he was to fulfill in Jerusalem, that is his Passion and Cross, and by implication the resurrection also. The blessed disciples were somewhat sleepy here, just as they took their ease when Christ was praying. This economy fulfilled human needs so that when they were wide awake they were able to behold this venerable and wonderful transformation. Thinking perhaps that the time of the Kingdom of God had arrived, the great Peter was glad that they were there talking on the mountain and He spoke out for three tabernacles to be built. He did not know what to say. For then it was not the time for the consummation of the age; nor in the present time are these saints to take their share in that hope which was promised to them. As Paul says: ‘He shall refashion the body of our lowliness to make it conform to the body of His glory (Phil 3.21),’ Christ’s no less. Since the economy was still in its early stages, not yet finished, how was it possible for Christ, who had come into the world for the sake of love, to draw back from his great desire to suffer on behalf of the world? He saved that nature which is under heaven by offering it to death according to the flesh, setting it free by his resurrection from the dead. This is why Peter did not know what to say. Moreover, apart from the marvelous and ineffable vision of Christ’s glory, something else happened that was both useful and necessary to confirm their faith (and not only for the disciples but for us as well) for from the cloud the voice of God the Father came down from Heaven saying: ‘This is my beloved Son in whom I am well pleased. Listen to Him.’ And it says that while this voice was speaking Jesus was found alone… For behold in the presence of Moses, the Father commands the apostles to listen to Christ. If he had wanted them to follow in the commandments of Moses surely he would have said ‘Keep the Law since you trust in Moses’. But God the Father does not say this. In the presence of Moses and his prophet Elijah he orders them to listen to Him [The Lord Jesus Christ]. And in order that no one might misrepresent the real meaning of the saying and pretend that the Father really ordered them to obey Moses and not Christ the Saviour of us all, this was why it was necessary for the evangelist to make a special note saying that when the voice came Jesus was found to be alone. And so when God the Father commanded the holy apostles from the cloud on high to ‘Listen to him’, Moses had gone away, Elijah was no longer present. Christ alone was there. God ordered them, then, to listen to him, for he is the end of the Law and the Prophets. For this reason he also spoke to the Jewish people in these words: ‘If you believed Moses you would have believed me, for he wrote about me.’ But since they had dishonoured the commandments of the most wise Moses and constantly nullified the words spoken through the prophets, rightly were they cast out and cut off from the good things promised to their fathers. As it is written: ‘Obedience is better than sacrifice. To listen is better than the fat of a lamb (1 Sam 15.22).’ This shows what happened to the Jews. But for us who recognized his appearing, all things in all manner are made good through him and with him who is the Christ, through whom and with whom, to God the Father, be glory and sovereignty, with the Holy Spirit, through the ages of ages, Amen.” St. Cyril of Alexandria, Hom. Diversae 9. PG 77.1009-1016. as translated in McGuckin, John Anthony. The Transfiguration of Christ in Scripture and Tradition. Vol. 9. Edwin Mellen Pr, 1986.
St. Cyril of Alexandria takes the transfiguration as a proof for the Lordship of the Incarnate Logos Who is Lord of the alive and of the dead. Moreover, His Lordship will extend to His descent into hades that He may destroy death by death. The Logos, Who is Life and Light by nature (as seen in the transfiguration), deigns to enter into human existence that He may destroy death by His death and resurrection. This promise of the destruction of death is shown to the believers who see Christ, of the same humanity as all of us, transfigured with His radiance as bright as the sun. This is the assurance that His entrance into our very live will give us a union with Life Itself. Inasmuch as He enters into us, we are offered the opportunity to enter into Him and be united to Him Whose flesh becomes the Life of us all as celebrated in the Eucharistic communion.
Because of our union with Him, we shall come to True Life and Existence. St. John writes,
“Behold what manner of love the Father has bestowed on us, that we should be called children of God! Therefore the world does not know us, because it did not know Him.Beloved, now we are children of God; and it has not yet been revealed what we shall be, but we know that when He is revealed, we shall be like Him, for we shall see Him as He is. And everyone who has this hope in Him purifies himself, just as He is pure.” 1 John 3.1-3.
We shall be like Him, for we shall see Him as He is. Christ, in His transfiguration, grants us the assurance of all of those who shall follow Him. To the extent that we die to those things which enslave us, we shall be granted this light, we shall be like Him.