The writer to the Hebrews gives us a deep insight of Jesus being our high priest and mediator. The priesthood in the Old Testament was given by God to those whose priesthood fell short, and He established a new priesthood. The old priesthood was set aside as it was weak, because the law never made anything perfect.
The old system established through Moses was a shadow. It was always His intention to install a new system and He took an oath to make it legal. The prophecy about Jesus recorded in Psalm 110:4 says, “you are a priest forever in the order of Melchizedek”. Read more: https://www.allnations.com.na/christ-the-perfect-mediator/