But when at length the Wisdom of God was manifested in the flesh, he fully unfolded to us all that the human mind can comprehend, or ought to think of the heavenly Father. Now, therefore, since Christ, the Sun of Righteousness, has arisen, we have the perfect refulgence of divine truth, like the brightness of noon-day, whereas the light was previously dim. It was no ordinary blessing which the apostle intended to publish when he wrote: “God, who at sundry times and in divers manners, spake in time past unto the fathers by the prophets, hath in these last days spoken unto us by his Son” (Heb. 1:1, 2); for he intimates, nay, openly declares, that God will not henceforth, as formerly, speak by this one and by that one, that he will not add prophecy to prophecy, or revelation to revelation, but has so completed all the parts of teaching in the Son, that it is to be regarded as his last and eternal testimony. For which reason, the whole period of the new dispensation, from the time when Christ appeared to us with the preaching of his Gospel, until the day of judgment, is designated by the last hour, the last times, the last days, that, contented with the perfection of Christ’s doctrine, we may learn to frame no new doctrine for ourselves, or admit any one devised by others. With good cause, therefore, the Father appointed the Son our teacher, with special prerogative, commanding that he and no human being should be heard. When he said, “Hear him” (Mt. 17:5), he commended his office to us, in few words, indeed, but words of more weight and energy than is commonly supposed, for it is just as if he had withdrawn us from all doctrines of man, and confined us to him alone, ordering us to seek the whole doctrine of salvation from him alone, to depend on him alone, and cleave to him alone; in short (as the words express), to listen only to his voice. And, indeed, what can now be expected or desired from man, when the very Word of life has appeared before us, and familiarly explained himself? Nay, every mouth should be stopped when once he has spoken, in whom, according to the pleasure of our heavenly Father, “are hid all the treasures of wisdom and knowledge” (Col. 2:3), and spoken as became the Wisdom of God (which is in no part defective) and the Messiah (from whom the revelation of all things was expected) (John 4:25); in other words, has so spoken as to leave nothing to be spoken by others after him.
Jean Calvin, Institutes of the Christian Religion, IV.VIII.7