The idea of Jesus being a High Priest continues. The writer observes that the High Priest is from among the people, represents the people in sacrificing for sin, understands human weakness to sin and is appointed by God. All of these traits were true of Jesus. We are going to hear more about a priest named Melchizedek later, but he was a priest to Abraham, the father of all of Israel. The writer breaks from his subject to scold his audience for their lack of understanding. What is being explained is something they should already have understood.
We should not be slow to learn like the original audience. Hardship should not be an excuse to fall away, but a reason to look at Jesus suffering for us and be willing to suffer for him.