Jesus took Peter, James, and John...

Thus, while the Transfiguration exalts Christ and shows forth his glory, the scene again foreshadows Christ’s destiny as the suffering servant who will die in Jerusalem for the sins of all humanity.

Ultimately, these two themes of Christ’s glory and his suffering are meant to go together, for God’s glory will be revealed most fully not in worldly splendor or self-exaltation but in his self-giving love for us on the cross. And these themes of the Transfiguration stand as a reminder to us: We are called to radiate God’s glory most splendidly through our own sacrificial love here on earth.

—from the book Praying the Rosary Like Never Before: Encounter the Wonder of Heaven and Earth

http://blog.franciscanmedia.org/minute-meditations/transfiguration-crucifixion-and-resurrection