“While he thus spake, there came a cloud, and overshadowed them: and they feared as they entered into the cloud.”
Luke 9:34 — Greek Interlinear
Church Fathers on Luke 9:34
While Christ is engaged in prayer, Peter is heavy with sleep, for he was weak, and did what was natural to man; as it is said, But Peter and they that were with him were heavy with sleep. But when they awake, they behold His glory, and the two men with Him; as it follows, And when they were awake, they saw his glory, and the two men that stood with him.
Or, by the word sleep, he means that strange maze that fell upon them by reason of the vision. For it was not night time, but the exceeding brightness of the light weighed down their weak eyes.
For the incomprehensible brightness of the Divine nature oppresses our bodily senses. For if the sight of the body is unable to contain the sun’s ray when opposite to the eyes which behold it, how can the corruption of our fleshly members endure the glory of God? And perhaps they were oppressed with sleep, that after their rest they might behold the sight of the resurrection. Therefore when they were awake they saw His glory. For no one, except he is watching, sees the glory…