The Holy Transfiguration of Our Lord God and Savior Jesus Christ

Discourse on the Holy Transfiguration of Our Lord God and Savior Jesus Christ of Saint Gregory Palamas, Archbishop of Thessalonica :
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"What does it mean to say: He was transfigured?" asks the Golden-Mouthed Theologian (Chrysostom). He answers this by saying: "It revealed something of His Divinity to them, as much and insofar as they were able to apprehend it, and it showed the indwelling of God within Him." The Evangelist Luke says: "And as He prayed, His countenance was altered" (Luke 9:29); and from the Evangelist Matthew we read: "And His face shone as the sun" (Mt.17:2). But the Evangelist said this, not in the context that this Light be thought of as subsistent for the senses (let us put aside the blindness of mind of those who can conceive of nothing higher than what is known through the senses). Rather, it is to show that Christ God, for those living and contemplating by the Spirit, is the same as the sun is for those living in the flesh and contemplating by the senses. Therefore, some other Light for the knowing the Divinity is not necessary for those who are enriched by Divine gifts.

That same Inscrutable Light shone and was mysteriously manifest to the Apostles and the foremost of the Prophets at that moment, when (the Lord) was praying. This shows that what brought forth this blessed sight was prayer, and that the radiance occured and was manifest by uniting the mind with God, and that it is granted to all who, with constant exercise in efforts of virtue and prayer, strive with their mind towards God. True beauty, essentially, can be contemplated only with a purified mind. To gaze upon its luminance assumes a sort of participation in it, as though some bright ray etches itself upon the face.

Even the face of Moses was illumined by his association with God. Do you not know that Moses was transfigured when he went up the mountain, and there beheld the Glory of God? But he (Moses) did not effect this, but rather he underwent a transfiguration. However, our Lord Jesus Christ possessed that Light Himself. In this regard, actually, He did not need prayer for His flesh to radiate with the Divine Light; it was but to show from whence that Light descends upon the saints of God, and how to contemplate it....

From OCA.org.