From Wikipedia:
Blockquote The transfiguration of Jesus is an event reported in the New Testament when Jesus is transfigured and becomes radiant in glory upon a mountain. The Synoptic Gospels (Matthew 17:1–8, Mark 9:2–8, Luke 9:28–36) describe it, and the Second Epistle of Peter also refers to it (2 Peter 1:16–18). It has also been hypothesized that the first chapter of the Gospel of John alludes to it (John 1:14).
The three gospel accounts are very similar. Here is Mark’s description:
Mark 9
2 And after six days Jesus took with him Peter and James and John, and led them up a high mountain by themselves. And he was transfigured before them, 3 and his clothes became radiant, intensely white, as no one on earth could bleach them. 4 And there appeared to them Elijah with Moses, and they were talking with Jesus. 5 And Peter said to Jesus, “Rabbi, it is good that we are here. Let us make three tents, one for you and one for Moses and one for Elijah.” 6 For he did not know what to say, for they were terrified. 7 And a cloud overshadowed them, and a voice came out of the cloud, “This is my beloved Son; listen to him.” And suddenly, looking around, they no longer saw anyone with them but Jesus only. 9 And as they were coming down the mountain, he charged them to tell no one what they had seen, until the Son of Man had risen from the dead. 10 So they kept the matter to themselves, questioning what this rising from the dead might mean.
Why the transfiguration? Why did the Lord show these three disciples His glory? Why did God tell them to listen to Him, calling Him his “beloved Son”? Why were they to keep quiet about what they had seen and heard until after His resurrection? I will leave it for others to address these questions.
We can only assume that these three disciples kept silent until after the Resurrection. I think I would have found it difficult not to tell my friends about the amazing event I had witnessed. They must have told Matthew, Mark and Luke, presumably after the resurrection had occurred! As far as I know, the only other corroboration of their story is Peter’s testimony in his second letter: I find it interesting that he makes no mention of the appearances of Moses and Elijah.
2 Peter 1
16 For we did not follow cleverly devised myths when we made known to you the power and coming of our Lord Jesus Christ, but we were eyewitnesses of his majesty.
17 For when he received honor and glory from God the Father, and the voice was borne to him by the Majestic Glory, “This is my beloved Son, with whom I am well pleased.”
18 We ourselves heard this very voice borne from heaven, for we were with him on the holy mountain.
In his epistle, Peter makes no mention of Moses and Elijah, but the three Gospel authors made a point of writing about their appearance with Jesus, and included Peter’s suggestion, as the practical man he was, that three tents should be built for them and Jesus. Typical Peter! It is reasonably suggested that Moses was there to personify the Law and Elijah the Prophets. But what did they actually see?
There has been a lot of discussion about the nature of man. Atheists believe than humans are no more than intelligent animals, a position adopted by most evolutionists who teach than we are were all evolved, eventually as a higher form of primate. The vast majority of Christians believe that our nature is more than animal because we were created as spiritual beings. That basic belief is divided among two positions. One holds that our nature is tri-partite - body, soul and sprit, or body, mind and spirit. The other position is that we are bi-partite – body and spirit. I personally take the view that we are bi-partite. The authors of the Westminster Confession taught that “Man was created as a direct act of God, in His image. Man is a “living soul,” composed of a physical (body) and a non-physical (spirit) element.” In other words, a bi-partite being.
So, what did the three disciples see on the top of that hill? Moses had been dead and buried for around 1,500 years and Elijah departed this life around 850 BC, so the disciples obviously did not see their bodies. They existed in their immortal spirits and it must have been their spirits that appeared with Jesus. They apparently communicated with Jesus. After God spoke from heaven, Moses and Elijah disappeared from view.
Do the spirits of departed believers appear today? Some time ago, I fell asleep as I was lying back in my recliner. I was not dreaming. I must have dozed for about 20 minutes or so, then I woke up. I was definitely wide awake. I glanced around. There, standing in the middle of the room was my wife Alida who had died on December 27, 2017 at the age of 72. I had watched as she breathed her last breath. I had observed how her face had literally glowed, how peaceful she seemed to be. At that moment her spirit must have left her body, taken by her heavenly Father Naturally, I think about her all the time, but I had never before seen her appear as she did that day. She looked as she had around the prime of her life, as lovely as ever. I wanted to talk to her but I couldn’t. I would have told her how much I loved her, how sorry I was for not having been a perfect husband, and so much more. All too soon, she vanished from sight. I’ll not be the same again. And, I now read the accounts of the Transfiguration from a very different perspective.