Although for many years thought to have been written by the apostle Paul, the book of Hebrews is now believed to have been authored by Barnabas, Paul's friend and a Jew of the priestly tribe of Levi. Or more likely Apollos, another associate of Paul who was a Jewish Christian intellectual from Alexandria. The book was written sometime prior to a.d. 70.
Primarily a written sermon that was perhaps first delivered in a synagogue and subsequently circulated, the book is aimed at those Jewish converts to Christianity who at the time were having difficulty letting go of Old Testament Jewish practices. The writer makes it clear that the purpose of all earlier religious practices is superseded by Jesus Christ. There is simply no more need to continue with them. Jesus Christ is sufficient for our salvation and is the complete and final revelation of God to humanity, fulfilling the Old Testament and establishing a new covenant or New Testament going forward.
This is a powerful message combining the promise of better things with a warning to not to ignore them.