The book of Hebrews begins by reminding us of the importance and supremacy of Jesus as God's only Son. He's greater than the prophets, angels, Moses, Joshua, the Old Covenant priesthood, and His grace is greater than the Law.
We're also reminded how Jesus' message and ministry was and is superior to the high priesthood of the Old Covenant—as an eternal High Priest like Melchizedek. Jesus is the mediator of a better covenant—relationship with God—and in His continuing ministry as our High Priest, He is personally involved in our faith and life as believers.