From the following fact we can prove that, many as were the actions that he repeatedly promised us that he would perform in due season, he even in part anticipated the appointed time in the performance of them, for our edification, that we might be fully convinced that whatsoever he has spoken will assuredly come to pass: He said that full of glory would be the resurrection of the saints, for “then shall the righteous shine forth as the sun in the kingdom of their Father” (Matthew 13:43), in order that he might be believed to speak truth, he granted the sight thereof before the time to the disciples. For he “took Peter and James and John, and went up into the mountain and was transfigured before them” (Luke 9:28), “and his face did shine as lightning, and his garments became white as snow” (Matthew 17:2).
Cyril the Great, from On John
Cyril the Great (also known as Cyril of Alexandria) lived from approximately AD376 to 444. He was Patriarch of Alexandria from 412 to 444, when the city was at the height of its power and influence in the Roman Empire. Cyril was a prolific author and was a leading voice in the controversies surrounding the person and work of Jesus Christ. His writings and theology are still considered fundamental to the tradition of the Church Fathers and all Orthodox Christians to this day.