In the Old Testament God spoke to our forefathers through prophets. In the New Testament God has spoken to us through his Son - an exact representation of God (see 1:1-3). Since we have flesh and blood, Jesus shared our humanity by being made like us "...in order that he might become a merciful and faithful high priest in service to God and that he might make atonement for the sins of the people..." (see 2:14-18). "...fix your thoughts on Jesus...Jesus has been found worthy of greater honor than Moses... Moses was faithful as a servant... But Christ is faithful as a son over God's house. ...and was designated by God to be high priest..." (3:1, 3, 5; 5:10). "Therefore, since we have a great high priest who has gone into heaven, Jesus the Son of God, let us hold firmly to the faith we profess." (4:14).
"If perfection could have been attained through the Levitical priesthood...why was there still need for another priest to come...one who has become a priest not on the basis of a regulation as to his ancestry but on the basis of the power of an indestructible life." (7:11, 16). "Unlike the other high priests, he (Jesus) does not need to offer sacrifices day after day... He sacrificed for their sins once for all when he offered himself." (7:27). The Levitical priesthood was temporary until God established an eternal priesthood through Jesus Christ - with a new covenant (see chapter 8).
"When Christ came as high priest... (he offered himself, unblemished to God, to) ...cleanse our consciences from acts that lead to death, so that we may serve the living God!" (9:11, 14). Christ's sacrifice was once for all time, see 10:1-18. "Therefore, brothers, since we have confidence... Let us hold unswervingly to the hope we profess... And let us consider how we may spur one another on toward love and good deeds." (10:19, 23, 24). Which we do by faith, see chapter 11; and see comments about faith under Romans. Keep your eyes on Jesus - chapter 12.
Look at the footnotes in your Bible. The Old Testament is referenced continually throughout the book of Hebrews. It is believed the author of Hebrews had a Jewish audience in mind.
The intent of law (whether its the 10 commandments, Mosaic laws, civil laws, proverbs, Jesus' command to LOVE, or some other law) is to help us live in harmony. No one on this earth is capable of keeping all of the laws, all of the time - regardless how hard we try. Actually, the more we know about the law and the more we try to obey the law, the more we discover we have failed - to the point where we just become overwhelmed! It is through FAITH we are able to spur one another on toward love and good deeds!
Addendum September 2007: Chapter 11 is very important--place a special marker there and read it often! "By faith we understand that the universe was formed at God's command..." (verse 3). Several examples are given of people who listened to the Word of God and acted according to His instructions. "These were all commended for their faith, yet none of them received what had been promised (a new heaven and earth)" (verse 39).