Jesus transfiguration represents much to the Christian. First, it symbolizes the fact that Christ intends to return because during the transfiguration, he promised he would return again and his body physically left this earth. Second, it demonstrates that God still loves man and has offered a Spirit, commonly referred to as the Holy Spirit, here on this earth to be a counselor to all who will pray and seek him. It also represents that Jesus is in heaven preparing a place for all Christians to come. The Christian notes that as time goes by, and heaven is still not prepared, Jesus is at work planning his big party for believers. This moment also built great responsibility in the disciples to carry Christ's cause forward to generations to come.
Here is a passage to support these claims (Matthew 17:2-9):
2There he was transfigured before them. His face shone like the sun, and his clothes became as white as the light. 3Just then there appeared before them Moses and Elijah, talking with Jesus.4Peter said to Jesus, "Lord, it is good for us to be here. If you wish, I will put up three shelters—one for you, one for Moses and one for Elijah."5While he was still speaking, a bright cloud enveloped them, and a voice from the cloud said, "This is my Son, whom I love; with him I am well pleased. Listen to him!"6When the disciples heard this, they fell facedown to the ground, terrified. 7But Jesus came and touched them. "Get up," he said. "Don't be afraid." 8When they looked up, they saw no one except Jesus. 9As they were coming down the mountain, Jesus instructed them, "Don't tell anyone what you have seen, until the Son of Man has been raised from the dead."
Finally, this time also signaled the completion of Jesus' work here on earth. God's pleasure with Jesus perfect life, death, and ressurection demonstrate closure to this passage of His Story.