Keep high the Feast!
St Gregory Palamas:
...“What does it mean to say: He was transfigured?” asks the
Golden-Mouthed Theologian (Chrysostomos). 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” (Lk 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 occurred 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
St Gregory's Sermon here.