CCC 444 The Gospels report that at two solemn moments, the Baptism and the Transfiguration of Christ, the voice of the Father designates Jesus his “beloved Son”.1 Jesus calls himself the “only Son of God”, and by this title affirms his eternal pre-existence.2 He asks for faith in “the name of the only Son of God”.3 In the centurion’s exclamation before the crucified Christ, “Truly this man was the Son of God”,4 that Christian confession is already heard. Only in the Paschal mystery can the believer give the title “Son of God” its full meaning.

CCC 516 Christ’s whole earthly life – his words and deeds, his silences and sufferings, indeed his manner of being and speaking – is Revelation of the Father. Jesus can say: “Whoever has seen me has seen the Father”, and the Father can say: “This is my Son, my Chosen; listen to him!”5 Because our Lord became man in order to do his Father’s will, even the least characteristics of his mysteries manifest “God’s love. .. among us”.6

CCC 554 From the day Peter confessed that Jesus is the Christ, the Son of the living God, the Master “began to show his disciples that he must go to Jerusalem and suffer many things. .. and be killed, and on the third day be raised.”7 Peter scorns this prediction, nor do the others understand it any better than he.8 In this context the mysterious episode of Jesus’ Transfiguration takes place on a high mountain,9 before three witnesses chosen by himself: Peter, James and John. Jesus’ face and clothes become dazzling with light, and Moses and Elijah appear, speaking “of his departure, which he was to accomplish at Jerusalem”.10 A cloud covers him and a voice from heaven says: “This is my Son, my Chosen; listen to him!”11

1 Cf. Mt 3:17; cf. 17:5.
2 Jn 3:16; cf. 10:36.
3 Jn 3:18.
4 Mk 15:39.
5 Jn 14:9; Lk 9:35; cf. Mt 17:5; Mk 9:7, “my beloved Son”.
6 Jn 4:9.
7 Mt 16:21.
8 Cf. Mt 16:22-23; 17:23; Lk 9:45.
9 Cf. Mt 17:1-8 and parallels; 2 Pt 1:16-18.
10 Lk 9:31.
11 Lk 9:35.