Today we remember the Transfiguration, a major feast in the Eastern churches but somewhat downplayed in the West. I offer three relevant quotes. The first is from Thomas Merton and is found in Merton and Hesychasm, Dieker and Montaldo eds., Louisville, Fons Vitae, 2003, pp. 231-232. The second is from Rowan Williams, The Dwelling of the Light, Grand Rapids, Eerdmans, 2003, pp. 11-12. The final excerpt is from Vincent Rossi's article "The Transfiguration of Creation", found here on an excellent website maintained by The Orthodox Fellowship of the Transfiguration.

Merton
The whole tradition of iconography represents a traditional experience formulated in a theology of light, the icon being a kind of sacramental medium for the illumination and awareness of the glory of Christ within us....What one "sees" in prayer before an icon is not an external representation of a historical person, but an interior presence in light, which is the glory of the transfigured Christ, the experience of which is transmitted in faith from generation to generation by those who have "seen", from the apostles on down....So when I say that my Christ is the Christ of the icons, I mean that he is reached not through any scientific study but through direct faith and the mediation of the liturgy, art, worship, prayer, theology of light, etc., that is all bound up with the Russian and Greek Tradition.

Williams
This is an icon of quite violent force, explosive quality; it shows an extreme experience. We may find it difficult to relate to at first for that reason: we may be struck and impressed by it, yet feel also that nothing in our own experience corresponds to this. We weren't there; we haven't seen the skys opening, the light suffusing the lonely figure on the rock, the weight of divine presence forcing us back, bowing us down. But the point of this, as of any icon, is not either to depict or to produce some kind of special experience in that sense: it is to open our eyes to what is true about Jesus and the saints. And what is true about Jesus is--if we really encounter it in its fullness--shocking, devastating: that this human life is sustained from the depths of God without interruption and without obstacle, that it translates into human terms what and who God the Son eternally is. The shock comes from realizing this means that God's life is compatible with every bit of human life, including the inner terrors of Gethsemane (fear and doubt) and the outer terrors of Calvary (torment and death)....But the point of this image of the transfiguration is to reinforce how the truth about Christ interrupts and overthrows our assumptions about God and about humanity.

Rossi
The disciples who witnessed the Transfiguration were also transfigured, not only in spirit and soul, but also in body. The uncreated light and grace of Christ, streaming from his transfigured face, body, and garments, transfigured the very senses of the apostles, allowing them to behold his glory, as of the only begotten of the Father, "full of grace and truth". Since the human nature shared by Christ with all humanity, according to the Fathers, is a microcosm of the whole created order, the fact that the transfigured body of Christ reveals his divinity in a flood of uncreated light, and that this same transfiguring uncreated energy streams from his face, body, and clothing and illuminates and transfigures the bodies of the apostles, means without doubt that the whole of creation is lifted up, and is meant to be lifted up, transformed and transfigured by the irresistible power of the grace of the Logos.