Joseph Benson's Commentary of the Old and New Testaments - Matthew 17:9
Matthew 17:9. Jesus charged them 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 should make others disbelieve it. “He knew,” says Macknight, “that the world, and even his own disciples, were not yet capable of comprehending the design of his transfiguration, nor of the appearing of Moses and Elias;... read more
Albert Barnes' Notes on the Whole Bible - Matthew 17:9
Tell the vision to no man - This vision was designed particularly to confirm them in the truth that he was the Messiah. While he was with them it was unnecessary that they should relate what they had seen. When he was crucified they would need this evidence that he was the Christ. Then they were to use it. There were three witnesses of it as many as the law required Deuteronomy 17:6; Hebrews 10:28, and the proof that he was the Messiah was clear. Besides, if they had told it then, it would have... read more