And as they came down from the mountain, Jesus charged them, saying, Tell the {e} vision to no man, until the Son of man be risen again from the dead.

(e) Which they saw, otherwise the word used in this place is usually used in referring to that which is seen in a dream.

People's New Testament

17:9 Jesus charged them, saying, Tell the vision to no man. Even they themselves did not yet understand what they had seen. Still less could they, in present circumstances, make others understand. All was plainer after Christ had died, risen, and had ascended to glory. The time had not come to proclaim the mystery of the Sonship of the world.

Wesley's Notes

17:9 Tell the vision to no man - Not to the rest of the disciples, lest they should be grieved and discouraged because they were not admitted to the sight: nor to any other persons, lest it should enrage some the more, and his approaching sufferings shall make others disbelieve it; till the Son of man be risen again - Till the resurrection should make it credible, and confirm their testimony about it.

Scofield Reference Notes

Margin Son of man

Also Mt 17:12,22, See Scofield Note: "Mt 8:20".

Matthew Henry's Concise Commentary

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.