Charlie recently spoke at a church and provided a 30 minute overview of the book of Hebrews. More specifically who the readers were and what persecution they were under, who Christ is and why the author is emphasizing His nature, His attributes, and His sacrifice.  The author of Hebrews spends and inordinate amount of time on emphasizing that Christ is superior to anything that came before. 

For further reading checkout gracenotes #39, How do we explain Hebrews 6:4-8