The Old Testament reading is taken from the prophet Daniel, chapter 7, verses 9-10 & 13-14
9 ‘As I looked,
‘thrones were set in place,
and the Ancient of Days took his seat.
His clothing was as white as snow;
the hair of his head was white like wool.
His throne was flaming with fire,
and its wheels were all ablaze.
10 A river of fire was flowing,
coming out from before him.
Thousands upon thousands attended him;
ten thousand times ten thousand stood before him.
The court was seated,
and the books were opened.
13 ‘In my vision at night I looked, and there before me was one like a son of man,[a] coming with the clouds of heaven. He approached the Ancient of Days and was led into his presence. 14 He was given authority, glory and sovereign power; all nations and peoples of every language worshipped him. His dominion is an everlasting dominion that will not pass away, and his kingdom is one that will never be destroyed.
The epistle is taken from the second letter to Peter, chapter 1, verses 16-19
16 For we did not follow cleverly devised stories when we told you about the coming of our Lord Jesus Christ in power, but we were eye-witnesses of his majesty. 17 He received honour and glory from God the Father when the voice came to him from the Majestic Glory, saying, ‘This is my Son, whom I love; with him I am well pleased.’[a] 18 We ourselves heard this voice that came from heaven when we were with him on the sacred mountain.
19 We also have the prophetic message as something completely reliable, and you will do well to pay attention to it, as to a light shining in a dark place, until the day dawns and the morning star rises in your hearts.
The Gospel of the apostle Luke, chapter 9, verses 28-36
28 About eight days after Jesus said this, he took Peter, John and James with him and went up onto a mountain to pray. 29 As he was praying, the appearance of his face changed, and his clothes became as bright as a flash of lightning. 30 Two men, Moses and Elijah, appeared in glorious splendour, talking with Jesus. 31 They spoke about his departure,[a] which he was about to bring to fulfilment at Jerusalem. 32 Peter and his companions were very sleepy, but when they became fully awake, they saw his glory and the two men standing with him. 33 As the men were leaving Jesus, Peter said to him, ‘Master, it is good for us to be here. Let us put up three shelters – one for you, one for Moses and one for Elijah.’ (He did not know what he was saying.)
34 While he was speaking, a cloud appeared and covered them, and they were afraid as they entered the cloud. 35 A voice came from the cloud, saying, ‘This is my Son, whom I have chosen; listen to him.’ 36 When the voice had spoken, they found that Jesus was alone. The disciples kept this to themselves and did not tell anyone at that time what they had seen.