Hebrews. An EXTREMELY important book. Just like Romans was a foundational book for the Gentiles, this is the counterpart to the Jews in Jerusalem. Think about this for a minute, before Christ came all Jewish people were taught to make atonement for their sins through animal sacrifice. It is an extremely important part of the religion and their way of life. So Christ comes as the Promised Messiah to fulfil all the ritual acts they were doing, specifically handed down from God himself. Before the Christ they lived a very legal life of order, sacrifice, hierarchy, priests…etc. So now that Jesus did come, and many Jews came to believe, what do you do with all they were taught their whole life. (some of you may be going through this personally as we read this New Testament together).
As long as there is a standing temple, the Jews (even Christian Jews) will feel this human effort desire to make sacrifices to the Lord. Makes sense, it would be really hard to literally change everything that was taught for 2000 years, right . So God breathes this letter through an un-named author, confirming all the Law was a SHADOW of The Christ. ALL of it. The tabernacle, the animal sacrifice, the feasts, the Priests were all a prophecy of the Christ to come. Shortly after this book is written to the Christian Jews, the Temple in Jerusalem will be destroyed, so God is preparing them for what is to come since only sacrifices and priests are part of a Temple. God needs to eliminate the temple to focus ourselves on Christ, not on ritual. See all that we learned in the Old Testament WAS a Shadow of Christ. To partake in any exercise that we think earns favor with the Lord in Salvation eliminates our Faith in the Messiah.
So if the Temple is about to be destroyed how does one approach God?