From a sermon on the transfiguration of the Lord by Anastasius of Sinai, bishop:
Upon Mount Tabor, Jesus revealed to his disciples a heavenly mystery. While living among them he had spoken of the kingdom and of his second coming in glory, but to banish from their hearts any possible doubt concerning the kingdom and to confirm their faith in what lay in the future by its prefiguration in the present, he gave them on Mount Tabor a wonderful vision of his glory, a foreshadowing of the kingdom of heaven. […]
These are the divine wonders we celebrate today; this is the saving revelation given us upon the mountain; this is the festival of Christ that has drawn us here. Let us listen, then, to the sacred voice of God so compellingly calling us from on high, from the summit of the mountain,
so that with the Lord’s chosen disciples we may penetrate the deep meaning of these holy mysteries, so far beyond our capacity to express. Jesus goes before us to show us the way, both up the mountain and into heaven, and - I speak boldly - it is for us now to follow him with all speed, yearning for the heavenly vision that will give us a share in his radiance, renew our spiritual nature and transform us into his own likeness, making us for ever sharers in his Godhead and raising us to heights as yet undreamed of.