As they were coming down the mountain, Jesus admonished them not to tell anyone what they had seen until the Son of Man had risen from the dead.
KJV
And as they came down from the mountain, he charged them that they should tell no man what things they had seen, till the Son of man were risen from the dead.
ASV
And as they were coming down from the mountain, he charged them that they should tell no man what things they had seen, save when the Son of man should have risen again from the dead.