Isaiah prophesied of the Messiah, the Suffering Servant: "Even as many were amazed at Him — so marred was His look beyond that of man, and His appearance beyond that of mortals" (Is 52:14). Isaiah's prophecy was fulfilled in Jesus' crucifixion and death. How could the severely altered face of the crucified Jesus be the face of God?
Jesus "was transfigured before their eyes, and His clothes became dazzlingly white — whiter than the work of any bleacher could make them" (Mk 9:2-3). At the Transfiguration, Jesus' face was no longer emptied (see Phil 2:7) of His divine glory. His face was clearly recognizable as the face of God.
We must never look at the crucified face of Jesus without remembering His transfigured face. Jesus' cross is not a denial of His divinity but can be understood only in the light of His divinity.
We must never look at the transfigured face of Jesus without also picturing the thorn-crowned face of the crucified Christ. Jesus' crucifixion takes us into the mysterious depths of His divinity.
There is an ancient tradition which holds that the Transfiguration took place forty days before Jesus' crucifixion and death. Thus, in 1457, Pope Callistus III set the date for the feast of the transfiguration: forty days before the feast of the Triumph of the Cross, September 14. The Transfiguration and crucifixion go together. Jesus is both fully God and fully man.