The apostles as witnesses of Christ’s majesty: For we have not followed cunningly devised fables when we made known unto you the power and coming of our Lord Jesus Christ, but were eye-witnesses of His majesty. V.17. For he received from God the Father honor and glory when there came such a voice to Him from the excellent Glory, This is My beloved Son, in whom I am well pleased. V.18. And this voice which came from heaven we heard when we were with Him in the holy mount.
What Peter and the other apostles had taught, also in the congregations of Asia Minor, was not a system of spiritual fables cleverly invented to bring them into subjection, after the manner of many false teachers; he was not writing down any human speculations and philosophies in giving them the proper information concerning the power and advent of Christ the Lord, of His return at the end of time, when He will be clothed with full majesty and power, in order to establish His kingdom forever. What Peter had been teaching with regard to this one fact was the truth, for which he could vouch with all the power at his command because he had been privileged to be an eye-witness of the glorification, of the majesty, of Christ.
The apostle states to which event he has reference: For He received from God the Father honor and glory when a voice was borne to Him of such a kind from the sublime Glory, This is My beloved Son, in whom I am well pleased.
That was the culminating incident in the happening on the Mount of Transfiguration, Matt. 17, 1-9: Mark 9, 2-8. Jesus, the poor, despised Prophet of Nazareth, who had come into His own and His own received Him not, was invested with honor and glory from His heavenly Father Himself. For while the three disciples, Peter, James, and John, were still lying upon the ground, almost stupefied by the miraculous brightness which surrounded them from heaven, they nevertheless could hear plainly the words which came down out of the cloud, the voice of God Himself, acknowledging Jesus as His true Son, His beloved Son, upon whom His good pleasure rested in full measure.
Concerning this Peter testifies: And this voice, borne from heaven, we heard when we were with Him on the holy mountain. Although the mountain was not in itself holy, this wonderful manifestation of the sublime, the splendid glory of God, sanctified and hallowed it for the time being. What Peter means to emphasize in this connection is this, that they, to whom was vouchsafed such a wonderful manifestation of the glory of God, were reliable witnesses, and therefore their Gospel could and should be accepted without question as the truth of the Lord.
Mark: This is one of the reasons why we also accept the Gospel as recorded by the apostles as the truth, because God would hardly have revealed Himself in such a manner to men that were hypocrites and swindler,