Book of Daniel 7:9-10.13-14.
As I watched : Thrones were set up and the Ancient One took his throne. His clothing was bright as snow, and the hair on his head as white as wool ; His throne was flames of fire, with wheels of burning fire.
A surging stream of fire flowed out from where he sat; Thousands upon thousands were ministering to him, and myriads upon myriads attended him. The court was convened, and the books were opened.
As the visions during the night continued, I saw One like a son of man coming, on the clouds of heaven; When he reached the Ancient One and was presented before him,
He received dominion, glory, and kingship; nations and peoples of every language serve him. His dominion is an everlasting dominion that shall not be taken away, his kingship shall not be destroyed.
The LORD is king; let the earth rejoice;
let the many islands be glad.
Clouds and darkness are round about him,
justice and judgment are the foundation of his throne.
The mountains melt like wax before the LORD,
before the Lord of all the earth.
The heavens proclaim his justice,
and all peoples see his glory.
You, O LORD, are the Most High over all the earth,
exalted far above all gods.
Holy Gospel of Jesus Christ according to Saint Mark 9:2-10.
Jesus took Peter, James, and John and led them up a high mountain apart by themselves. And he was transfigured before them,
and his clothes became dazzling white, such as no fuller on earth could bleach them.
Then Elijah appeared to them along with Moses, and they were conversing with Jesus.
Then Peter said to Jesus in reply, "Rabbi, it is good that we are here! Let us make three tents: one for you, one for Moses, and one for Elijah."
He hardly knew what to say, they were so terrified.
Then a cloud came, casting a shadow over them; then from the cloud came a voice, "This is my beloved Son. Listen to him."
Suddenly, looking around, they no longer saw anyone but Jesus alone with them.
As they were coming down from the mountain, he charged them not to relate what they had seen to anyone, except when the Son of Man had risen from the dead.
So they kept the matter to themselves, questioning what rising from the dead meant.
The Lord of both old and new
At the time of the Transfiguration the witness given to the Son was confirmed by both the voice of the Father and by Moses and Elijah, who appeared beside Jesus as his servants. The prophets are looking at Peter, James and John the apostles; the apostles behold the prophets. In one and the same place the princes of the old covenant come together with those of the new. Holy Moses saw Peter the holy one; the shepherd chosen by the Father saw the shepherd chosen by the Son. The former had rebuked the sea in days of old that God’s people might pass through the midst of its waves, the latter suggested setting up a tent to shelter the Church. The chaste man of the Old Testament saw the chaste man of the New: Elijah could see John. He who was lifted up in a chariot of fire saw him who rested on the breast of the Fire (Jn 13,23). And then the mountain became the symbol of the Church: at its summit Jesus unifies the two Testaments that this Church gathers up. He made it known that he is Lord of the one as of the other, of the Old which received his mysteries, of the New which revealed the glory of his actions.