Wow!! There is a lot in today's reading. If you have not read it I encourage you to do so now, prior to reading the rest of my comments.
Today's reading begins with the proclamation that Jesus Christ is the mediator of a new covenant. Jesus secured the forgiveness of our sins. The first covenant was when Moses brought the law (the Ten Commandments and several others) to the Hebrews. During the first covenant man could stay in communion with God by obeying the law. However, when man broke the law (i.e., sinned) the covenant became ineffective and a priest had to sacrifice an animal (shed the animal's blood) in order that the sin be forgiven. In a simplistic view, someone or something had to pay for that sin.
Jesus Christ's sacrifice earned the forgiveness of our sins. Jesus shed his blood so we would not have to experience spiritual death - eternal separation from God. This act created a new covenant between God and man.
All people die physically. It is the one, and only, thing we all must do. Christ died so we would not have to die spiritually. Christ died so that we can live.
Paul reminds us that the sacrifice Christ made for us does not have to be repeated. Christ was sinless and he volunteered to die for us. This act of love was so great that it can bear the weight of all of our sins. The sacrifice was so large that it can atone for the sins of all of us who have lived or are yet to live. Can you imagine how big this sacrifice must have been? Can you imagine how perfect Jesus was to carry this burden? Can you imagine how much love he must have for us to make this sacrifice?
Wishing you much success in your walk with Christ,