Did they (Peter, John, and James at the Transfiguration) realize what was going to happen? It is not likely, judging from the naivete of their reactions. They climbed the mountain with him; but, as we have said, we cannot speak of a prayer which would be strictly theirs. They are simply engulfed in the radiance of Jesus. Their contemplation does not spring forth from their own depths, but is an overflow of the prayer of Jesus which descends upon them. Today, ‘God himself has shone in their hearts to radiate the knowledge of his glory, the glory on the face of Christ’ (2 Corinthians 4:6).
We should see in them much more than simple witnesses: they truly participate in the mystery which is being accomplished before their eyes, in so far as they receive that which Jesus gives them in simplicity and humility. God is content with this good will; even as Peter makes a remark which betrays his lack of understanding of the situation, the cloud through which they will enter into intimacy with the Father is already approaching.
‘A bright cloud covered them with its shadow.’ We find here the hallmark of the most solemn moments in salvation history, when God chooses to reveal his greatest secrets. On Sinai, Moses entered into a cloud before Yahweh revealed his name to him. In like manner, at the dedication of the new temple, Solomon found himself taken up into a cloud as Yahweh came to take possession of his dwelling place. Finally, at the Annunciation, is this not the characteristic sign of the presence of God that the angel gives to the Virgin: “The Holy Spirit will come upon you and the power of the Most High will cover you with its shadow’?
Here, the, are three poor disciples, men of no exceptional merit, who enter into the cloud, the loftiest image of divine power. They have direct access to the Father, for they are close to Jesus and are his friends. Their dullness, their incomprehension, does not matter, their hearts are given totally to Jesus and that is enough. –‘The Wound of Love’ A. Carthusian Miscellany