1 After six days, Jesus took with him Peter, James, and John his brother, and brought them up into a high mountain by themselves. 2 He was changed (transfigured) before them. His face shone like the sun, and his garments became as white as the light. 3 Behold, Moses and Elijah appeared to them talking with him.
4 Peter answered and said to Jesus, "Lord, it is good for us to be here. If you want, let's make three tents here: one for you, one for Moses, and one for Elijah."
5 While he was still speaking, behold, a bright cloud overshadowed them. Behold, a voice came out of the cloud, saying, "This is my beloved Son, in whom I am well pleased. Listen to him."
6 When the disciples heard it, they fell on their faces, and were very afraid. 7 Jesus came and touched them and said, "Get up, and don't be afraid." 8 Lifting up their eyes, they saw no one, except Jesus alone.
9 As they were coming down from the mountain, Jesus commanded them, saying, "Don't tell anyone what you saw, until the Son of Man has risen from the dead."
Obviously what happened here was an event of power. The disciples already knew that Jesus was a man of power -- they might have felt, if not consciously thought, that he was a god. In this event, he is revealed as God, but perhaps more importantly, as a true servant of God. God validates his son.
To those who see through the eyes of power, the Transfiguration separates disciples from Jesus. The disciples will never have Jesus' power. They are subject to the absolute power of his glory. But if you see how the point of the Transfiguration is for God to validate his son, then you see how the disciples are kin to Jesus. If they obeyed God as sons, as Jesus did, God could say of each of them "Behold my beloved son, in whom I am well pleased. Listen to him."