Matthew 17:1-5

Mat 17:1 (KJB)
And after six days Jesus taketh Peter, James, and John his brother, and bringeth them up into an high mountain apart,

Traditionally speaking this high mountain, Mount Tabor, was the site of the transfiguration of Jesus but there is nothing to support it. It is more likely that it was Mount Meron (Jebel Jermuk) which was 12 miles (19 km) northwest of Capernaum which is the area where they were at. Instead of Jesus taking all the disciples with Him, He had only taken Peter, James, and John which is sometimes called Jesusí inner circle. This was not just a hill but a high mountain.

Mat 17:2 (KJB)
And was transfigured before them: and his face did shine as the sun, and his raiment was white as the light.

Then Jesus left them a little distance away and was transfigured from an ordinary human being into what He would have looked like in all His glory in Heaven. His face was shining as the sun because of the glory beaming from it and His clothes was as bright as the light. Peter, James, and John had to be qualified to see this or else they would have been consumed by the glory. The glory which Jesus exuded was not coming at Him but rather it was emanating out from Him. For those few moments, He was endowed with His glorified, heavenly body. This event could have happened at night since Luke records that Peter, James, and John were heavy with sleep. (Luke 9:32 KJV) But Peter and they that were with him were heavy with sleep: and when they were awake, they saw his glory, and the two men that stood with him.

Mat 17:3 (KJB)
And, behold, there appeared unto them Moses and Elias talking with him.

(Mal 4:4-5 KJV) Remember ye the law of Moses my servant, which I commanded unto him in Horeb for all Israel, with the statutes and judgments. {5} Behold, I will send you Elijah the prophet before the coming of the great and dreadful day of the LORD: Malachi records both the names of Moses and Elijah. It is not specifically known what they spoke about but it is believed they spoke about Jesus fulfilling all the Scriptures in the law and the prophets who prophesied His coming and death and resurrection. It was a heavenly witness of the ministry of the Lord Jesus Christ.

Mat 17:4 (KJB)
Then answered Peter, and said unto Jesus, Lord, it is good for us to be here: if thou wilt, let us make here three tabernacles; one for thee, and one for Moses, and one for Elias.

Then Peter makes one of his understatements in that he stated it was good for them to be there. Peter was looking at this event as some type of permanent event in that he wanted to make tabernacles for them or he wanted to extend the time they were there. It is very interesting that Peter recognizes both Moses and Elijah. No one told him who they were but this may answer a question many Christians have and that is, will we know each other in Heaven? Elijah lived about 900 years prior and Moses lived about 1500 years prior so how could Peter know who they were unless we will have full knowledge of everyone in Heaven, even those who lived hundreds of years ago. I believe this verse answers the question if we will know each other in Heaven. We must stop thinking earthly and transplanting those thoughts and scenarios to Heaven which will be a perfect environment.

Mat 17:5 (KJB)
While he yet spake, behold, a bright cloud overshadowed them: and behold a voice out of the cloud, which said, This is my beloved Son, in whom I am well pleased; hear ye him.

Then all of a sudden while Peter is still speaking, God the Father from Heaven forms a cloud of glory around Jesus, Moses, and Elijah and simultaneously truncates Peterís speech. God informs the three disciples that Jesus is His beloved Son and they were to listen to Him. Peter was probably talking and God wanted the disciples to listen to Jesus and not Peter. Peter wanted to stay on the Mount longer but God told them that they must listen to Jesus and He will guide them in the coming weeks. The appearance of this cloud was the culmination of this event.