By Understanding who this book was written for we can understand better some of it meaning. The book of Hebrews was written for the jew so that they would understand this new concept of Jesus. That is why the Author needed to prepare them by stating that Jesus was better than Angles, Moses, and more. Moses and the Angles were responsible for giving the jews there information. Angles spoke to them and told them God's wishes, and Moses gave them the torah. I am sure that this was a hard sell to a jew that Jesus was set above them. Now read the book with that im mind.

Hebrews 1:1-6 and Hebrews 3:1-6