What is this? A new teaching with authority. He commands even the unclean spirits and they obey him. (MK 2.26)
Commentary by St. John Henry Newman
At the appointed time, Christ came forth from the Father and showed himself in this external world, first as its Creator, then as its teacher, the revealer of secrets, the mediator, the effluence of God's glory. and the express image of his person.
Neither cloud nor image, emblem nor words, are interposed between the Son and his eternal Father. No language is needed between the Father and him, who is the very Word of the Father; no knowledge is imparted to him, who by his very nature and from eternity knows the Father and all that the Father knows.
Such are his own words, "No one knows the Son but the Father, neither does anyone know the Father except the Son, and anyone to whom the Son chooses to reveal him." Again, he says, "Whoever has seen me has seen the Father"; and he accounts for this when he tells us that he and the Father are one, and that he is in the bosom of the Father and so can disclose him to humankind, as he was still in heaven, even while he was on earth. Accordingly, the blessed apostle draws a contrast between Moses and Christ, to our comfort. "The Law," he says, 'was given by Moses, but grace and truth came by Jesus Christ." In him God is fully, and truly seen, so that he is absolutely the way, and the truth, and the life. All our duties are summed up for us in the message he brings us.
Those who look towards him for teaching, who worship and obey him, will by degrees see "the light of the knowledge of the glory of God in his face, and will be changed into the same image from glory to glory." And thus it happens that people of the lowest class and the humblest education may know fully the ways and works of God; fully, that is, as human beings can know them; far better and more truly than the most sagacious of this world from whom the gospel is hidden.
Religion has a store of wonderful secrets which cannot be communicated to others, but which are most pleasant and delightful to know. "Call on me," says God by the prophet, "and I will answer you, and show you great and mighty things of which you have no knowledge." This is no mere idle boast, but a fact which all who seek God will find to be true, though they cannot perhaps clearly express their meaning.
Strange truths about ourselves, about God, about our duty, about the world, about heaven and hell, new modes of viewing things, discoveries which cannot be put into words, marvelous prospects and thoughts half understood, deep convictions inspiring joy and peace, these are a part of the revelation which Christ, the Son of God, brings to those who obey him. Moses had much toil to gain from the great God, some scattered rays of the truth, and that for his personal comfort, not for all Israel; but Christ has brought from his Father for all of us the full and perfect way of life. Thus, he brings grace as well as truth, a most surprising miracle of mercy.
Speaking with Authority From PAROCHIAL AND PLAIN SERMONS 1 124-6 - MODERNIZED