The church was necessary down through the ages. Jesus was not the only high priest. There were high priests among the Old Testament brethren. A slayer was to abide in a city or refuge until the death of the High Priest. Every high priest taken from among men is ordained after the order of Melchizedek.
Every high priest is ordained to offer gifts and sacrifices.
There is No More Revelation the Heavens Are Sealed. Common belief of Protestants. Where there is no vision, the people perish. Daniel God reveals wisdom, knowledge, and secrets. In the last days God would pour out his spirit upon all flesh.