Matthew 17:9

9. Vision Or sight. The word does not intimate that it was not a reality. Tell the vision to no man, until… risen from the dead Just so the Lord in the last chapter forbade them to tell any one that he was the Christ. See our comment on Matthew 16:20. It was not until they had beheld all the scenes of his death and resurrection, and been empowered by the Spirit from on high, that they were competent to preach the Messiah as he is. Silence and discipline were their present duty. How could they properly preach a crucified and risen Saviour, when they were resolutely opposed to his death, (Matthew 16:20,) and, according to Mark, they questioned what the rising from the dead might mean? They had, indeed, preached in the earlier part of his ministry. But they had only preached repentance because the kingdom of heaven was at hand.

Had they preached the Messiah now they would hardly have held him forth as a dying Redeemer. And had they preached him as a glorious Messiah, superior to Moses and Elias, as set forth in his transfiguration, the Jewish authorities would have held them guilty of treason.