The letter to the Hebrews is structured around comparisons that demonstrate the superiority of the “word spoken in the Son” over past revelations “spoken in the prophets,” including Moses. Jesus surpasses even the Great Lawgiver.
The previous words provided by the Hebrew prophets were true but partial and preparatory. But now, “upon the last of these days,” God has “spoken” with great finality in one who is a “Son.”
And since this word is complete, it is “better than” the partial revelations of the past. “Having achieved the purification of sins,” the Son sat down at God’s right hand as the “appointed heir of all things.” And that means the word spoken “in the prophets” failed to achieve the “purification of sins.”
After demonstrating Christ’s superiority over the angels, the letter warns that if the previous incomplete word included “just recompense” for disobedience, so, now, believers cannot escape a far worse punishment if they ignore the word “spoken in the Son” - (Hebrews 2:1-4).
Hebrews demonstrates the superiority of the new “sonly” word by contrasting his priesthood, covenant, and sacrifice to the Levitical priesthood, covenant, and repeated animal sacrifices performed in the ancient Tabernacle.
The fact that God promised a future priesthood “after the order of Melchizedek” demonstrates beyond doubt that the Levitical priesthood is incapable of achieving the “purification of sins.”
And that priestly order requires multiple priests and animal sacrifices, and it was received at Mount Sinai as an integral part of the Torah. Therefore, and quite logically, the promised change in the priesthood means also a “change of law”:
(Hebrews 7:11-12) – “If indeed, therefore, there had been a perfecting through means of the Levitical priesthood, for the people thereon have had based a code of laws, what further need was there according to the order of Melchizedek for a different priest to be raised up, and not according to the order of Aaron? For seeing there is to be a change of the priesthood, of necessity, of law, also, comes a change.”
Due to human mortality, the Levitical priesthood is dependent on lineal descent and multiple generations of priests. Humanity's frailty was always the weakness of the system. Therefore, a fundamental change in the law was necessary, or at least, a change in the law of the priesthood and the system of animal sacrifices.
THE NEW HIGH PRIEST
In contrast, the priesthood “after the order of Melchizedek” is perpetual since it is based on the endless resurrected life of the Son. He is, therefore, the “priest forever” who serves in the “real Tabernacle not made with hands” for his people - (Hebrews 7:15-17).
Unlike the Levitical priests, the priest, singular, after the “order of Melchizedek” is installed by the declared word of Yahweh - (“Yahweh swore and will not regret: You are a priest everlastingly”), and, therefore, he holds the priesthood “un-transmissible.”
Moreover, he became the “guarantor of a better covenant” and saves “to the uttermost” everyone who approaches God through him because he “lives evermore to intercede in their behalf” - (Hebrews 7:19-25).
Under the old system, once each year, the high priest entered the “holy of holies” with blood from sacrificial animals to stand briefly where he applied the blood of animals to cleanse the sins of the nation committed in the preceding year.
In contrast, Jesus entered the “real sanctuary” once-for-all with his own blood to atone for the sins of his people, then he “sat down on the right hand of the throne of the Majesty in the heavens” where he remains to this day.
The old priesthood with its animal sacrifices were mere “glimpses and shadows of the heavenly realities,” just as Moses was told to make the earthly Tabernacle “according to the pattern he had seen in the mount” - (Hebrews 8:1-5).
Jesus is also the mediator of a better covenant legislated on better promises. If the “first covenant” had been faultless, there would have been no need for a second one. However, having found fault with it, the Lord announced the coming days when “I will conclude a new covenant” - (Hebrews 8:6-7).
And according to Hebrews, the new covenant is NOT “according to the covenant” made at Sinai. It is NOT a “renewed” or modified covenant, but something new, one that is necessary because the old legislation is incapable of “achieving the purification of sins” - (Hebrews 8:8-13).
By establishing the promised new covenant, Jesus made the “first one obsolete.” Even now. it in the process of disappearing, at least, from the perspective of the epistle.
Thus, the jurisdiction of the Levitical code over the conduct, hopes, and beliefs of the people of God is superseded by the “word of the Son.” Therefore, anyone who wishes to remain under the old system chooses that which is obsolete and incapable of cleansing the stain of sin.