Levi fathered the tribe from which the priests of old covenant Israel were chosen, but God did not intend for the Levitical priesthood to last forever. He would eventually replace it with the priestly order of Melchizedek, as Psalm 110 reveals. Yet, long before Psalm 110 was written and even before Levi was born, there were hints that the Melchizedekian priesthood would replace the priestly order of Levi. As Hebrews 7:1–10 argues, Melchizedek was greater than Abraham and thus greater than Abraham’s grandson Levi. The implication is that the Melchizedekian order of priests is therefore greater than the Levitical order.
Today’s passage argues forthrightly for the inferiority and inadequacy of the Levitical priesthood in comparison to the priestly order of Melchizedek. The author of Hebrews notes, drawing from Psalm 110, that perfection was unattainable under the Levitical system, enshrined in the Mosaic law of the old covenant, and thus a greater order was necessary. The contrast, then, is that the priestly order of Melchizedek does actually bring the perfection that people need to stand in the presence of God (Heb. 7:11).
But if the approved priestly order is changed and taken away from Levi, there must be a change in the law as well (v. 12). This must be so, because it is impossible for the Mosaic law to continue without the Levitical priests. As the book of Leviticus reveals, for example, the Levitical priests maintained the boundaries between clean and unclean, and they offered the sacrifices needed for God to forgive the Israelites’ breaking of the law. It is inconceivable that the Mosaic law could go on without the temple and Levites, though that does not mean God’s moral law goes away once the Mosaic law is fulfilled. The Mosaic law contains elements of God’s moral law within it, but the moral law transcends the Mosaic administration.
The legal change is needed to qualify Jesus as our High Priest, for under the Mosaic law, Jesus cannot be a priest since He comes from the tribe of Judah (Heb. 7:13–14). The Mosaic law grants the office of king, not the priesthood, to Judah’s tribe (Gen. 49:8–12). However, since Jesus is clearly our High Priest, He must belong to the order of Melchizedek, as David in Psalm 110 foresaw the day when the Judahite king would be of that priesthood, and thus that the law would change. The arrival of the Melchizedekian High Priest means a change in how God administers His covenant with His people.