In the presence of chosen witnesses the Lord unveils his glory, investing with such splendor that bodily appearance which he shares with the rest of the human race that his face shines like the sun and his clothes become white as snow.

The primary purpose of this transfiguration was to remove the scandal of the cross from the hearts of Christ's disciples; the greatness of his hidden glory was revealed to them to prevent their faith being shaken by the self-abasement of the suffering he was voluntarily to undergo.

In his foresight, however, he was also laying the foundations of the Church's hope, teaching the whole body of Christ the nature of the change it is to receive, and schooling his members to look forward to a share in the glory which had already shone forth in their head.

The Lord had told them of this when he spoke of his coming in majesty: “Then shall the just shine like the sun in the kingdom of their Father.”

The blessed apostle Paul bears witness to the same thing: “I consider that the sufferings of this present time are not worth comparing with the glory that is to be revealed in us.”

And again: “You have died, and your life is hidden with Christ in God. When Christ who is your life appears, then you also will appear with him in glory.”

Still further instruction was to come from the transfiguration to fortify the apostles and perfect their understanding. Moses and Elijah, representing the law and the prophets, appeared in conversation with the Lord.

Thus through the presence of these five men the saying was fulfilled: “On the evidence of two or three witnesses every work shall stand.”

What could be more firmly established than that Word in whose proclamation the trumpets of Old and New Testaments sound in unison, and the writings of ancient witnesses are in perfect accord with the teaching of the gospel?

The pages of both covenants agree with one another. He who had been promised beforehand by mysteriously veiled signs was now revealed clearly and distinctly in the radiance of his glory, since, as Saint John says. “The Law was given by Moses, but grace and truth have come through Jesus Christ.”

In Christ what was promised by prophetic figures and what was signified by legal precepts are alike fulfilled, for by his presence he teaches the truth of the prophecies, and by grace he makes it possible for us to obey the commandments.

May we all therefore be confirmed in our faith through the preaching of the holy Gospel, and let no one be ashamed of the cross by which Christ has redeemed the world.

None of us must be afraid to suffer for the sake of justice or doubt the fulfillment of the promises, for it is through toil that we come to rest and through death that we pass to life.

If we continue in the acknowledgment and love of Christ who took upon himself all the weakness of our lowly nature, what he conquered we too shall conquer, and the promise he gave us we shall receive.

So then, whether it is to encourage us to obey his commands or to endure hardships, let the Father's voice always be ringing in our ears and telling us: “This is my beloved Son in whom I am well pleased: listen to him.”

(Sermon 51, 3-4. 8: PL 54, 310-311. 313)

Leo the Great (c.400-461) was elected pope in 440. At a time of general disorder he did much to strengthen the influence of the Roman see. Although he was not a profound theologian, Leo's teaching is clear and forceful. His Tome was accepted as a statement of Christological orthodoxy at the Council of Chalcedon (451). One hundred and forty-three of his letters and ninety-six sermons have survived. The latter, which cover the whole of the liturgical year, have been published in a critical edition.