What does Hebrews 7:13 mean?
Under the law of Moses, all priests were members of the tribe of Levi. This passage, however, has been speaking of the Old Testament figure of Melchizedek, who was not part of that line. In fact, he predates the tribe of Levi, and was given tithes and honors by Abraham himself (Genesis 14:14–24; Hebrews 7:4–7). In this way, Melchizedek is clearly a greater figure than Abraham, and his priesthood is clearly greater than that of Levi or Aaron.The promises of God also separated the priesthood, through the tribe of Levi, from the throne, through the tribe of Judah. And yet, as earlier verses in Hebrews have shown, the Promised One is described as both a king and a priest. Melchizedek, then, serves as a foreshadowing of the ministry of Christ. He is greater than Abraham (John 8:53), predates the Law of Moses (John 8:58), and is without beginning or end (John 1:1–3). This not only means Christ can be the fulfillment of prophecy, He is the only one who can fulfill God's plan to perfectly—completely—provide for mankind's salvation. If the Levitical priesthood was able to accomplish this, God would never have promised, after Levi, to establish Melchizedek's order forever (Hebrews 7:11).