The book of Hebrews, which is clearly directed at fellow Hebrews, is unique in that it deals with the sonship of Christ, His priesthood and sacrifice from a Hebrew perspective more thoroughly than any other book in the New Testament, making it essential reading for all those who want to have a deeper understanding of Christ's suffering, death, resurrection and ascension..
Almost the whole of this letter focuses on the exposition of first testament passages, using Jewish methods of interpretation common in synagogues of the day. However Paul (the assumed author for this book) differs from Jewish interpreters in that he sees Christ as the fulfilment of the first testament prophecies and teaching, emphasising that Christ is God's final word to man, making sense out of God's previous revelation, for by God speaking at various times and in many different ways shows the incompleteness of the first testament revelation.
Central to the message of Hebrews is a comparison between Israel in the wilderness and the new church, between the covenant received by the children of Israel at Sinai and the new covenant in Christ's blood. It also explains why the high priesthood of Christ is superior to that of Aaron, in that it was established before the high priesthood of Aaron by the Son of God before His coming to earth as a man.
The church on earth is related to God in heaven, just as Israel once stood before Him at Sinai, and just as God spoke to them so He has spoken to us, thus the disobedience of Israel in the wilderness after their meeting with God on Sinai is cited as an example for Christians to avoid.
The covenant established at Sinai has been replaced by the better covenant established by Christ, because under the old covenant God could not be approached directly because of sin, and animal sacrifices merely covered over sin they did not totally cleanse the sinner.
Through the second covenant, however, because of the selflessness of Christ dying as a perfect man in place of man, complete forgiveness has been made available to those truly repentant through the forgiveness of sin and even the cleansing of the conscience of the sinner, allowing complete and free access to God through the Son. The graciousness of the new covenant makes our obedience to the will and purposes of God all the more important.
In the letter the superiority of the new covenant, is demonstrated by a comparison between the Mediator of the new covenant and the mediators of the old. That is the angels, who were active in the giving of the law on Sinai (Acts 7:38; Gal. 3:19), and especially Moses, were the mediators of the old covenant. The priesthood and sacrifices as required by the old covenant were carried out by Aaron. Hebrews compares Jesus with the angels (1:1 - 2:18), Moses (3:1 - 6) and Aaron (4:14 - 10:21).
These comparisons show clearly that Jesus surpasses the revelation of God given at Sinai. Indeed, as God's Son He is in a class by Himself and that the one who is the Son is also appointed to be the eternal high priest (5:1 - 10). By the obedient sacrifice of Himself, He has provided forgiveness, cleansing and access to God the Father, and is even now in heaven helping us as our advocate, which help the priesthood of Aaron was unable to provide.
Finally, God's faithful servants, both priestly and non-priestly, provide us with examples of perseverance even in the most difficult and traumatic of circumstances, challenging us to endure in our day (11:1 - 40). However Christ Himself is our prime example (12:1 - 11).