Jesus realized that the apostles needed a mountain experience because He was on His way to Jerusalem to suffer and die. He knows that the apostle’s faith will be tested and be brought to its breaking point. To be able to sustain them so that they will not break in their faith was to allow them to have a glimpse of His divinity. It means that Jesus had to take his apostles up the mountain for moments which they will not forget and which will give them courage and motivation to go on when things get rough.
First, Jesus showed them his Godhead in the transfiguration. Secondly, he also showed them that the whole Scripture, represented by Moses and Elijah, was backing him up. In effect, Jesus was sending a clear signal to his disciples to hold on to what they experience at the mount of transfiguration, so that they will not fall apart. The overwhelming experience of the disciples was endorsed by no less than the Father himself, “This is my beloved Son, with whom I am well pleased, listen to him.” As a Father, he will never abandon his Son even in death.
