Towards the end of the Transfiguration story, a cloud overshadowed them. In Jewish thought the presence of God is regularly connected with the cloud. It was in the cloud that Moses met God. It was in the cloud that God came to the Tabernacle, etc. And it was also the dream of the Jews that when the Messiah comes the cloud of God’s presence would return to the Temple. This descent of the cloud in our Gospel is a way of saying that the Messiah had come.
For the Jews a case must be proven by 3 witnesses (Deut 19:15), that’s why Jesus took the 3 apostles, Peter, James and John with him. And during the Transfiguration, he was seen talking with the 3 other great witnesses: Moses, who was the supreme law-giver of Israel, and Elijah, who was the first and the greatest of the prophets. Then the Voice of God was heard, which assured the world that his will rest on Jesus, being His beloved Son. They were giving “a green light” to Jesus to “go on” with his mission; he was assured that he was on the right way to the cross. It is also worth noting that this Transfiguration event can be found in the three synoptic Gospels, Mark (9), Luke (9) and Matthew (19). This similarities of their writings proved that this transfiguration experience did actually happen.
The Transfiguration erased the fears of the apostles caused by Jesus’ statement that he was going to Jerusalem to die. It was the complete negation of all that they understood of the Messiah. His exposition of his passion did not only baffle their minds but broke their hearts too. And what they witness in Mt. Tabor gave them something to hold on to, something to hope for. Even they could not fully understand their wonderful experience with Jesus’ transfiguration was enough for them to feel secured and at peace. They can not control such enormous joy in their hearts that made them exclaimed, “Teacher, it is good for us to be here.”