The Transfiguration and the walking on the water are glimpses of the beauty and the effortless power over all matter which will belong to men when they are really waked by God.
The bright cloud overshadowing the Saints is the Power of the Father, or perhaps the Holy Spirit; or I may also venture to call the Saviour that bright cloud which overshadows the Gospel, the Law, and the Prophets, as they understand who can behold His light in all these three.
The voice out of the cloud speaks either to Moses or Elias, who desired to see the Son of God, and to hear Him; or it is for the teaching of the Apostles.
This is the Son, this the Beloved, this the Accepted; and He it is who is to be heard, as the voice out of the cloud signifies, saying, Hear ye Him. For He is a fit teacher of doing the things He has done, who has given the weight of His own example to the loss of the world, the joy of the cross, the death of the body, and after that the glory of the heavenly kingdom.
He enjoins silence respecting what they had seen, for this reason, that when they should be filled with the Holy Spirit, they should then become witnesses of these spiritual deeds.
When the Lord threatens, He shows a dark cloud, as on Sinai; but here where He sought not to terrify but to teach, there appeared a bright cloud.
Neither Moses, nor Elias speak, but the Father greater than all sends a voice out of the cloud, that the disciples might believe that this voice was from God. For God has ordinarily shown Himself in a cloud, as it is written, Clouds and darkness are round about Him; (Ps. 97:2.) and this is what is said, Behold, a voice out of the cloud.
Fear not then, Peter; for if God is mighty, it is manifest that the Son is also mighty; wherefore if He is loved, fear not thou; for none forsakes Him whom He loves; nor dost thou love Him equally with the Father. Neither does He love Him merely because He begot Him, but because He is of one will with Himself; as it follows, In whom I am well pleased; which is to say, in whom I rest content, whom I accept, for all things of the Father He performs with care, and His will is one with the Father; so if He will to be crucified, do not then speak against it.
But when before in Christ's baptism, such a voice came from heaven, yet none of the multitude then present suffered any thing of this kind, how is it that the disciples on the mount fell prostrate? Because in sooth their solicitude was much, the height and loneliness of the spot great, and the transfiguration itself attended with terrors, the clear light and the spreading cloud; all these things together wrought to terrify them.
While they thought only of an earthly tabernacle of boughs or tents, they are overshadowed by the covering of a bright cloud; While he yet spake, there came a bright cloud and overshadowed them. (Exod. 19:9, 16.)
Forasmuch as Peter had asked unwisely, he deserves not any answer; but the Father makes answer for the Son, that the Lord's word might be fulfilled, He that sent me, he beareth witness of me. (John 5:37.)
The voice of the Father is heard speaking from heaven, giving testimony to the Son, and teaching Peter the truth, taking away his error, and through Peter the other disciples also; whence he proceeds, This is my beloved Son. For Him make the tabernacle, Him obey; this is the Son, they are but servants; and they also ought as you to make ready a tabernacle for the Lord in the inmost parts of their heart.
Their cause of terror is threefold. Because they knew that they had done amiss; or because the bright cloud had covered them; or because they had heard the voice of God the Father speaking; for human frailty cannot endure to look upon so great glory, and falls to the earth trembling through both soul and body. And by how much higher any one has aimed, by so much lower will be his fall, if he shall be ignorant of his own measure.
And whereas they were laid down, and could not raise themselves again, He approaches them, touches them gently, that by His touch their fear might be banished, and their unnerved limbs gain strength; And Jesus drew near, and touched them. But He further added His word to His hand, And said unto them, Arise, fear not. He first banishes their fear, that He may after impart teaching. It follows, And when they lifted up their eyes, they saw no man, save Jesus only; which was done with good reason; for had Moses and Elias continued with the Lord, it might have seemed uncertain to which in particular the witness of the Father was borne. Also they see Jesus standing after the cloud has been removed, and Moses and Elias disappeared, because after the shadow of the Law and Prophets has departed, both are found in the Gospel. It follows; And as they came down from the mount, Jesus charged them, saying, Tell no man this vision, until the Son of Man shall rise from the dead. He will not be preached among the people, lest the marvel of the thing should seem incredible, and lest the cross following after so great glory should cause offence.
He says therefore, Hear ye Him, as much as to say, Let the shadow of the Law be past, and the types of the Prophets, and follow ye the one shining light of the Gospel. Or He says, Hear ye Him, to show that it was He whom Moses had foretold, The Lord your God shall raise up a Prophet unto you of your brethren like unto me, Him shall ye hear. (Deut. 18:18.) Thus the Lord had witnesses on all sides; from heaven the voice of the Father, Elias out of Paradise, Moses out of Hades, the Apostles from among men, that at the name of Jesus every thing should bow the knee, of things in heaven, things on earth, and things beneath.
Whereas the holy Apostles fell upon their faces, that was a proof of their sanctity, for the saints are always described to fall upon their faces, but the wicked to fall backwardsa.
Or, because if His majesty should be published among the people, they should hinder the dispensation of His passion, by resistance to the chief Priests; and thus the redemption of the human race should suffer impediment.
Also in supposing that tabernacles were to be built for conversation in heaven, in which houses are not needed, as it is written in the Apocalypse, I saw not any temple therein. (Rev. 21:22.)
(ap. Anselm.) It is to be observed, that the mystery of the second regeneration, that, to wit, which shall be in the resurrection, when the flesh shall be raised again, agrees well with the mystery of the first which is in baptism, when the soul is raised again. For in the baptism of Christ is shown the working of the whole Trinity; there was the Son incarnate, the Holy Ghost appealing in the figure of a dove, and the Father made known by the voice. In like manner in the transfiguration, which is the sacrament of the second regeneration, the whole Trinity appeared; the Father in the voice, the Son in the man, and the Holy Spirit in the cloud. It is made a question how the Holy Spirit was shown there in the dove, here in the cloud. Because it is His manner to mark His gifts by specific outward forms. And the gift of baptism is innocence, which is denoted by the bird of purity. But as in the resurrection, He is to give splendour and refreshment, therefore in the cloud are denoted both the refreshment and the brightness of the rising bodies. It follows, And when the disciples heard it, they fell on their faces, and feared greatly.
Consider the details of this passage. See if you can also say this: The disciples understood that the Son of God had been speaking with Moses. It was Moses who had said of God, “No one shall see my face and live.” The disciples understood the testimony of Moses about God. They were not able to endure the radiance of the Word. They humbled themselves under the mighty hand of God.But after the touch of the Word, they lifted up their eyes. They saw Jesus only and no other. Moses, the law and Elijah the prophet had become one with the gospel of Jesus. They did not abide as they formerly were as three, but they became one. Think of these things in a spiritual sense.
(Verse 8.) But lifting up their eyes, they saw no one except Jesus alone. Reasonably, after they had risen, they saw no one except Jesus alone: lest if Moses and Elijah had continued with the Lord, the uncertain voice of the Father would be seen, to whom he would give the testimony. Therefore, they see Jesus standing, the cloud having been taken away, and Moses and Elijah had vanished: because after the shadow of the Law and the Prophets had departed, which had covered the apostles with its veil, both lights are found in the Gospel.
. Not able to endure the brightness of the cloud, nor the voice, the disciples fell to the ground. Their eyes were also heavy with sleep, as Luke says (See Lk. 9:32.), ("sleep" indicating the daze caused by the vision). Lest the fear grip them for a long time and obliterate the memory of what they had seen, the Lord rouses them and reassures them. He is seen to be alone, so that you will not imagine that the voice was for Moses or Elijah; indeed, the voice was for Christ, as He is the Son.
[AD 1963] CS Lewis on Matthew 17:1-8