171 Six days later, three of them saw that glory. Jesus took Peter and the brothers, James and John, and led them up a high mountain. 2 His appearance changed from the inside out, right before their eyes. Sunlight poured from his face. His clothes were filled with light. 3 Then they realized that Moses and Elijah were also there in deep conversation with him. 4 Peter broke in, "Master, this is a great moment! What would you think if I built three memorials here on the mountain - one for you, one for Moses, one for Elijah?" 5 While he was going on like this, babbling, a light-radiant cloud enveloped them, and sounding from deep in the cloud a voice: "This is my Son, marked by my love, focus of my delight. Listen to him." 6 When the disciples heard it, they fell flat on their faces, scared to death. 7 But Jesus came over and touched them. "Don't be afraid." 8 When they opened their eyes and looked around all they saw was Jesus, only Jesus. 9 Coming down the mountain, Jesus swore them to secrecy. "Don't breathe a word of what you've seen. After the Son of Man is raised from the dead, you are free to talk." 10 The disciples, meanwhile, were asking questions. "Why do the religion scholars say that Elijah has to come first?" 11 Jesus answered, "Elijah does come and get everything ready. 12 I'm telling you, Elijah has already come but they didn't know him when they saw him. They treated him like dirt, the same way they are about to treat the Son of Man."
Matthew Henry's Commentary on Matthew 17:1-12
Commentary on Matthew 17:1-13
(Read Matthew 17:1-13)
Now the disciples beheld somewhat of Christ's glory, as of the only begotten of the Father. It was intended to support their faith, when they would have to witness his crucifixion; and would give them an idea of the glory prepared for them, when changed by his power and made like him. The apostles were overcome by the glorious sight. Peter thought that it was most desirable to continue there, and to go no more down to meet the sufferings of which he was so unwilling to hear. In this he knew not what he said. We are wrong, if we look for a heaven here upon earth. Whatever tabernacles we propose to make for ourselves in this world, we must always remember to ask Christ's leave. That sacrifice was not yet offered, without which the souls of sinful men could not have been saved; and important services were to be done by Peter and his brethren. While Peter spoke, a bright cloud overshadowed them, an emblem of the Divine presence and glory. Ever since man sinned, and heard God's voice in the garden, unusual appearances of God have been terrible to man. They fell prostrate to the earth, till Jesus encouraged them; when looking round, they beheld only their Lord as they commonly saw him. We must pass through varied experiences in our way to glory; and when we return to the world after an ordinance, it must be our care to take Christ with us, and then it may be our comfort that he is with us.