Jesus took his 3 closest disciples (Peter, James, and John) with him to a high mountain. Jesus went up to the mountain to pray, and while he was praying his disciples became sleepy. They woke up to Jesus transfigured. What does "transfiguration" mean? That's just a fancy way of saying he "changed appearance" ("trans" means "change" and "figure" refers to Jesus' appearance). His appearance changed in two ways: his face was shining as bright as the sun and his clothes were whiter than you can imagine.
They saw 2 other people talking with Jesus about the fact that he was getting ready to depart, to leave earth and return to the heavens. Peter was so confused, he didn't really know what to say. You can imagine him just trying to come up with something, so he said, "Jesus, should we build shelters for the three of you?" While he was speaking, the voice of God from heaven began speaking: "This is my Son, and I love him. I am very pleased with him. Listen to him!" (Matthew 17:6)
The sound of the voice of God was just too much for the three disciples, and they fell to the ground terrified. Jesus approached them, told them not to be afraid and to get back up. When they looked up, Moses and Elijah were gone. As they went down the mountain, Jesus told them not to share their experience with anyone until after his resurrection.
Which Mountain Was the Transfiguration On?
None of the 3 gospels report the name of this mountain, so we can only guess. Historically, Mount Tabor was the leading candidate as it is a striking mountain very near the western part of the Sea of Galilee where Jesus did much of his ministry. There is an ancient church on the top of the mountain now because of this tradition.
Others think the Transfiguration occurred on Mount Hermon because it is the largest mountain in the region and it is close to Caesarea Philippi, which is where both Matthew and Mark place the disciples and Jesus in the chapter just before this story in their respective gospels.
Why Did Moses and Elijah Appear with Jesus?
First, nothing in the actual narrative names Moses and Elijah, so we don't actually know how Peter, James and John knew it was those two figures. But the story doesn't record every word of their conversation. It does say that the 3 were discussing Jesus' soon "departure," so perhaps something in that conversation made it obvious to them. Or maybe, as they were walking back down the mountain, one of the disciples asked Jesus, "Who were those guys?!?!"
Now, as to why those two figures were the ones who met Jesus on that mountain, we can only explore the Biblical themes going through the Old Testament to understand the significance.
Jesus Fulfilled the Law and the Prophets
In Matthew 5:17, Jesus said, "Do not think I have come to get rid of what is written in the Law or in the Prophets. I have not come to do that. Instead, I have come to give full meaning to what is written." God gave Moses the Law on Mount Sinai. Elijah was arguably the most famous prophet and was the first major prophet to call Israel to repentance after the kingdom split. So those two people could be said to represent the Law and the Prophets that Jesus came to fulfill. This was them "passing the baton" to Jesus for him to finish his fulfillment.
Shared Mountaintop Experiences
Both Moses and Elijah had "mountaintop" experiences with God on Mount Sinai. Moses received the Law there, and Elijah heard from God in his "still, small voice" on Mount Sinai in 1 Kings 19. So here they are, all 3 on top of a mountain again, experiencing the very presence of God together.
Unusual Ends to their Lives
In Deuteronomy 34:6, we learn that God himself buried Moses on the top of Mount Nebo, a mountain overlooking the Promised Land that Moses was not allowed to enter. "To this day no one knows where his grave is."
In 2 Kings 2 we learn that God took Elijah from earth into heaven on a chariot of fire without dying.
Of course, Jesus died and then 3 days later rose from the grave!
Jesus Fulfilled Old Testament Prophecy about the Messiah
Moses, in his final speech to the Israelites before they entered the promised land, actually predicted a coming figure that would be raised up from Israel: "The LORD your God will raise up for you a prophet like me from among you, from your fellow Israelites. You must listen to him." (Deuteronomy 18:15)
Because of Elijah's strange departure from earth, many Jews of his day associated the promised Messiah with Elijah himself returning. That's why the Jewish leaders actually asked John the Baptist if he was Elijah in John 1:21. In John 6, after Jesus fed the 5,000, the crowd immediately assumed he was "The Prophet" they were waiting on. See Peter's sermon in Acts 3:12-26.
Why Did Peter Want to Build Three Shelters?
Another word for "shelter" here is "tabernacle." Peter asked Jesus if he could build 3 "tabernacles" for Jesus, Moses and Elijah. It seems like Peter thought it was a good idea for them all to stay up there as long as they could. God's voice didn't correct him directly, but ignored the idea.
Also, remember that the Tabernacle in the Old Testament was the place where God's presence dwelled among the Israelites as they were wandering the wilderness after the Exodus. Maybe Peter was trying to come up with some plan to capture the moment and keep God's presence there? He didn't realize that God's presence (through his Holy Spirit) was going to be poured out on all believers on Pentecost!
What did God say on the Mount of Transfiguration?
In Matthew 17:5, God spoke and said, "This is my Son, and I love him. I am very pleased with him. Listen to him!" In Matthew 3:17, when Jesus was being baptized, God spoke and said, "This is my Son, and I love him. I am very pleased with him." Sound familiar?
It seems like God was publicly putting his stamp of approval on Jesus at the beginning and the end of his ministry.
Why Did Jesus Tell Them to Keep It Quiet?
This is another question the story just doesn't give us the answer to. Jesus often told people to not tell others about miracles he had done, or to keep quiet the fact that he was the Messiah. We can only say that Jesus had a reason to tell them this and it served his purposes better for them to keep it quiet until after his resurrection.
After all, according to Luke 9:31, the discussion the 3 of them were having was about his "departure," or literally his "exodus." As soon as you hear the word "exodus" in the same conversation as Jesus predicting his death, burial and resurrection, you should be thinking of the Passover, Israelites being redeemed from the Egyptians, and that whole story. Jesus was determined to accomplish his purpose and in his wisdom, he knew that sharing this experience before his death and resurrection was not going to help that.
Where Is the Transfiguration in the Bible?
You can find the Transfiguration in Matthew, Mark, and Luke (also known as the "synoptic" gospels). John does not record the Transfiguration in his gospel. Transfiguration Bible verses: Matthew 17:1-9, Mark 9:2-8, Luke 9:28-36