I recently ran across a 1941 address by Archbishop Fulton Sheen where he comments on Peter's attitude towards the Transfiguration:
"Is not our nation today very much like Peter on the mountain of the Transfiguration, who, seeing the face of Our Lord blazing as the sun and His garments white as snow as he spoke with Moses and Elias, cried out in the ecstasy of joy: "Lord, it is good for us to be here. Let us build three tabernacles: one for Thee, one for Moses and one for Elias." Peter felt that everything should be kept just as it was; that the present transient glory should be captured, and that the status quo should be preserved in its totality.
"But not so with the Saviour. While Peter was saying: "Stay here on the Mount of the Transfiguration," Our Lord was practically saying: "Go to Mount Calvary." While Peter was contemplating building tabernacles, Our Lord was talking to Moses and Elias of His death. Peter was concerned only with saving: but the Saviour's interest was in regeneration.
"Peter did not understand that the vision of glory which he was bequeathed was in the future, not the present, and in order to attain it one had to take up a Cross. There were two beats in the Transfiguration: Withdrawal and return. Withdrawal from the present glory for a crucifixion and a return to a greater glory because of it. This momentary detachment from present glory of the Saviour's was not a truancy to duty; it was a withdrawal according to plan to seize the initiative at another time and in another way."