The subject of priesthood is here continued, after the parenthesis which extended from verse 11 of chapter 5 to the end of chapter 6. The closing words of the previous chapter mentioned the fact that the priesthood of Christ is after the order of Melchisedec; and in the seventh chapter the Spirit of God develops the surpassing excellency which characterizes it. We are told very little about Melchisedec in the Old Testament; the only notices we have of him being in Genesis 14 and Psalm 110. The great object of his introduction in Genesis was, doubtless, in order to serve as a type of Christ, for Christ was ever the One in the thoughts and mind of God from the beginning. Melchisedec was both a king and priest—priest of the Most High God. He is brought abruptly on the scene after Abraham had returned victorious over the worldly powers: and the title here given to God—Most High—we find again in Daniel 4, where the humbled king owns God as the Most High, who rules in the kingdom of men and gives it to whomsoever He will. So, in another Old Testament scripture, we read, "He [Christ]...shall sit and rule upon His throne; and He shall be a priest upon His throne" (Zech. 6:13). This will be fulfilled during His millennial reign on earth.
But the great point in the chapter before us is to show that the priesthood of Christ is after the order of Melchisedec and not after the order of Aaron, as well as to bring out the many points of superiority of the former—a superiority which necessarily belongs to Him who is both God and man in one person. As a priest Melchisedec's descent was not reckoned as that of the Aaronic priests must be (see Ezra 2:62), nor had he end of life, whereas the sons of Aaron were only to be numbered from thirty years old to fifty. The superiority of Melchisedec is further shown, inasmuch as even the patriarch Abraham paid tithes and received a blessing from him, and unquestionably the less is blessed of the better. With divinely given skill the inspired writer proves that the whole order of things is changed: for perfection was not by the Levitical priesthood; if it had been there would have been no need for another priest to arise, after the order of Melchisedec, and not after the order of Aaron. And with the change of the priesthood, there comes necessarily a change of the law. But even Melchisedec, exalted as he was, was but a shadow: Christ is the substance, and Judaism, with its types and shadows, passes away, while Christ and Christianity remain.
Further, our Lord did not spring from the priestly tribe of Levi, but from Judah: His priesthood was not, therefore, hereditary, as was Aaron's. Nor was it brought to an end by death, for it was not after the law of a carnal commandment, but after the power of an endless life.
We should notice that the word "did," in italic print in verse 19, should be left out: the passage will then read thus: “For there is a setting aside of the commandment going before for its weakness and unprofitableness, (for the law perfected nothing,) and the introduction of a better hope” (Hebrews 7:18-19 JND). This little word "better" is found in Hebrews about thirteen times, and marks the contrast between those blessings which we have under Christianity, and the state of things which previously existed under the law. The priests of old were made so without the swearing of an oath: but Jesus with an oath, and that the oath of Him who will not repent—Jehovah Himself. Then, again, the Aaronic priests did not continue, for death overshadowed everything in this world, and they too were mortal men who died. But Christ continues ever, and His priesthood is intransmissible; that is, it does not pass from father to son. Having drawn out so fully the contrast as between the priesthood of Christ and that of Aaron, and having shown in so many ways the dignity and surpassing excellence of the former, our Epistle proceeds to unfold the blessed results for us. He is able to save—not merely in a temporary way—but right on to the end, all those who approach to God by Him. Christ ever lives, never dies, therefore His intercession is permanent and abiding. We read in chapter 2—where it was a question of meeting the claims of a holy God and glorifying Him about sin—that "it became" God that He should die; nothing else could adequately meet the case. Here in chapter 7, such a High Priest "became us"; One who could exercise a continuous and unchanging priesthood, according to all the dignity and value of His Person, before God. He is holy, harmless, undefiled, separated from sinners and made higher than the heavens. Wondrous privilege to have such a High Priest making intercession for us! The High Priest of old offered up sacrifices "daily," and both for his own and the people's sins; but Christ offered up Himself, once for all, never to be repeated. The High Priests under the law were merely men, who had infirmity; but the Christian's High Priest is the Son, who is "consecrated for evermore."