Chapters 5 and 6 detoured from the main theme in order to present a warning about faithlessness and apostasy. Chapter 7 returns to the topic of Melchizedek, who represents a *mysterious* but important moment in Old Testament history. Here, the author will show how Melchizedek was superior to Abraham, and that Melchizedek's priesthood is superior to the priesthood of Aaron. This leads into the next chapters, which show how Jesus Christ perfectly fulfills our salvation in ways which the Old Covenant cannot (BibleRef).