And as they came down from the mountain, Jesus charged them, saying,
Tell the vision to no man, until the Son of man be risen again from the dead.
All Commentaries on Matthew 17:9 Go To Matthew 17
Jerome
AD 420
The preview of the future kingdom and the glory of his triumph had been shown on the mountain. So he does not want this to be told to the people in case it should be deemed incredible because of its greatness and also so that after such great glory the event of the cross that follows should not cause untaught minds to stumble. .