The transfiguration of Jesus’ body is an exclusive “invitation-only” event. The short list includes James, the first of the twelve who will die for Christ, John, the one to die last, and Peter, the hard head or “rock”. These guys are eye witnesses to a completely transcendent event. Therefore, they will serve as such when the time is right. But for now, they’re overcome with fear, being placed in unfamiliar circumstances with no understanding of the event at its unfolding.
Fear notwithstanding, Peter presumes to speak to the occasion saying that it’s good that they’re here. True enough, but Peter is nonetheless speaking from ignorance. For, in this highly endorphin-laced state, Peter seems bent on having the experience last indefinitely. “It is good for us to be here” implying it’s so much better here than hanging out amongst the crowds. His thought is to set up dwelling places for Moses, Elijah and Jesus, perhaps to live out his life right here in the company of them. Of course, such a plan would come at the cost of sharing Jesus and the Gospel with the world. Alas, we’ll need to look no further than verses 17-19 to see what becomes of the other disciples without Jesus, at least at this point in their spiritual development.
Instead of individual tabernacles, God provides a single shelter of cloud, covering them all, and speaks into it. It’s as if the whole event was to introduce the Voice. Note here that once God speaks, the visual purpose has been fulfilled. Christ is returned to His familiar state and life goes on. Jesus charges Peter, James and John not to speak of this at this time. For one thing, they should consider themselves privileged enough without making the others feel badly for missing out on this one. More to the point, they still don’t get the fact that Jesus has just given them a glimpse of his glorified and time-transcending body as a foreshadowing of his death-conquering sacrifice. But, they will.