In some ways chapter 8 is an extended commentary on 7:22, where the author introduces the concept covenant. He explains the word by quoting at length from a prophetic passage in the Book of Jeremiah. Yet he fails to interpret the term covenant. He does that in the following chapter (9:15-22). The quotation from Jeremiah 31:31-34, however, serves the purpose of showing the readers that God himself in the days of Jeremiah had already declared the covenant made with Israel to be obsolete.
God revealed the appearance of the new covenant centuries before the birth of Christ. Just as God himself appointed Christ as high priest in the order of Melchizedek, so he established a new covenant of which Christ would be the high priest.
The old order of the Levitical priesthood eventually had to come to an end. The sanctuary at which the priests served was “a copy and shadow of what is in heaven.” By contrast, the sanctuary at which Jesus serves as high priest is the true tabernacle in the presence of God himself. The earthly sanctuary was temporal; the heavenly sanctuary is eternal.
As the heavenly tabernacle is superior to the earthly sanctuary, so the new covenant, of which Jesus is the mediator, is superior to the old covenant. The new covenant is better because of the promises God gives to his people. And Jesus, who is the mediator of this new covenant, guarantees these promises: to know God, to treasure his revelation, and to experience complete forgiveness of sin.
To point out the supremacy of Christ’s priesthood, the author of Hebrews presents a description of the earthly tabernacle, its contents, and the priestly ministry in and around this sanctuary. The sacrifices, however, were external observances, for they were unable to cleanse the guilty conscience of the sinner.