When God speaks of a new covenant or agreement, He makes the first one obsolete (out of use). And what is obsolete (out of use and annulled because of age) is ripe for disappearance and to be dispensed with altogether. (Hebrews 8:13 AMP)
This letter to the Hebrews sets forth the all-inclusive revolution or reconstitution which God made when He brought His Son, Jesus Christ, into the world - that is, the religious revolution. This revolution, which was rejected by Judaism, has been almost entirely overlooked or lost sight of by Christendom since Apostolic times. The entire present system of Christianity as generally accepted would be impossible if the meaning of this letter were received as a heavenly revelation in the power of the Holy Spirit. That is - if it came into the heart by the Spirit's power with the effect of a revelation in the same way as the Apostle Paul came to see who "Jesus of Nazareth" is, then a Christian-Judaism, or Judaistic-Christianity (which Christendom so largely is) would be impossible; as it became in his own case. The Letter to the Hebrews is only one other aspect of the battle fought out in the Letters to the Romans and Galatians.
In the light of such a spiritual eye-opening a whole lot of things would go: but being a "heavenly vision," there would be no tears, no sense of loss, and no fond farewells. The gain and joy would rather put all such things into the category of a worn-out and no-longer-to-be-desired suit of clothes. In saying this we are only contemplating the full-tide of spiritual life known before any of these things came into being. These things only came in when the fullness of the Spirit had gone out, and, being an artificial substitute, they can never but be limiting things in the realm of Divine purpose. And yet, behold how these things have become the very nature of traditional and organized Christianity! So much so that to touch them in any way which threatens their existence is to meet something more bitter and formidable than any persecution from the world. This is not said carelessly. Religion can be, and is very largely, a terrible force; and Christianity has become a religion. There are very few communities of Christians - even the most evangelical, and spiritual - who wholly escape the tendency or propensity to persecute or ostracize other bodies of Christians who might be regarded as rivals in their field of activity... "God... hath at the end of these days spoken... in His Son." But the new era and new order had brought out a new and mightier-than-ever conflict.
By T. Austin-Sparks from: "God Hath Spoken" - Chapter 1