This is probably the toughest book in the New Testament to understand. The main problem is that some people that the author is writing to are tempted to stop being Christians and go back to being Jews. So the author explains why Jesus is better and everything they ‘re thinking of going back to is worse. Jesus is better than the angels, he is better than Moses, he is better than all of the temple ceremonies and sacrifices. Interwoven in this explanation are repeated warnings in which the author tells his hearers that if they leave Jesus and the church, they are leaving eternal life and they will not be saved. The warnings are very severe, because the danger is so great.
Thanks again for these summaries. They come in handy for refreshing my memory on various points I should be able to remember.