"Transfiguration" of Jesus

“After six days Jesus took Peter, James and John with him. He led them up a high mountain. They were all alone. There in front of them his appearance was changed. His clothes became so white they shone. They were whiter than anyone in the world could bleach them. Elijah and Moses appeared in front of Jesus and his disciples. The two of them were talking with Jesus.
Peter said to Jesus, ‘Rabbi, it is good for us to be here. Let us put up three shelters. One will be for you, one for Moses, and one for Elijah.’ Peter didn't really know what to say, because they were so afraid.
Then a cloud appeared and surrounded them. A voice came from the cloud. It said, ‘This is my Son, and I love him. Listen to him!’
They looked around. Suddenly they no longer saw anyone with them except Jesus.
They came down the mountain. On the way down, Jesus ordered them not to tell anyone what they had seen. He told them to wait until the Son of Man had risen from the dead.”
Mark 9:2-9 (This story is also found in Matthew 17:1-9 and Luke 9:28-36.)

This event in the Bible is called The Transfiguration. It was intended to prove that Jesus is the Son of God and that Jesus is God. The glory of God in Jesus was clearly seen by human eyes, although covered with a human body during Jesus’ life.

When Jesus went up the mountain, He took three disciples with Him (Peter, James, & John). As Jesus was changed (or transfigured), Moses and Elijah appeared and the voice of God was heard. We can observe that there were three witnesses on earth and three witnesses in heaven to give credibility to Whom Jesus was. “Therefore, the Old Testament law of three witnesses required to attest to any fact (Deuteronomy 19:15) was satisfied both in earth and in heaven.” (2)

(Moses was significant to the Jews as representing the Law. Elijah represented the Prophets and was also important to the Jews. Some would say that because Moses and Elijah disappeard that Jesus is the only One to hear. However, God is the same yesterday, today, and forever. So I believe that there is value in the Old Testament, and Life through Jesus in the New Testament of the Bible.)

The disciples then would not doubt Jesus’ divinity or that His Words came from God. Peter later wrote about what they had seen, “We told you about the time our Lord Jesus Christ came with power. But we didn't make up stories when we told you about it. With our own eyes we saw him in all his majesty. God the Father gave him honor and glory. The voice of the Majestic Glory came to him. It said, ‘This is my Son, and I love him. I am very pleased with him.’ We ourselves heard the voice that came from heaven. We were with him on the sacred mountain.” 2 Peter 1:16-18

“The disciples, who had only known Him in His human body, now had a greater realization of the deity of Christ, though they could not fully comprehend it. That gave them the reassurance they needed after hearing the shocking news of His coming death.” (1).

Sources:
1. http://www.gotquestions.org/transfiguration.html
2. http://www.allaboutjesuschrist.org/transfiguration-of-jesus-christ-faq.htm
3. http://www.gospelway.com/topics/bible/transfiguration.php