Transfiguration Sunday: Who is this?

Mark 9:2-9

Mark 9:2-9 The Transfiguration 2 After six days Jesus took Peter, James and John with him and led them up a high mountain, where they were all alone. There he was transfigured before them. 3 His clothes became dazzling white, whiter than anyone in the world could bleach them. 4 And there appeared before them Elijah and Moses, who were talking with Jesus. 5 Peter said to Jesus, “Rabbi, it is good for us to be here. Let us put up three shelters—one for you, one for Moses and one for Elijah.” 6 (He did not know what to say, they were so frightened.) 7 Then a cloud appeared and covered them, and a voice came from the cloud: “This is my Son, whom I love. Listen to him!” 8 Suddenly, when they looked around, they no longer saw anyone with them except Jesus. 9 As they were coming down the mountain, Jesus gave them orders not to tell anyone what they had seen until the Son of Man had risen from the dead.