Hebrews 8:6

In this part of the chapter, the apostle illustrates and confirms the superior excellency of the priesthood of Christ above that of Aaron, from the excellency of that covenant, or that dispensation of the covenant of grace, of which Christ was the Mediator (Heb 8:6): his ministry is more excellent, by how much he is the Mediator of a better covenant. The body and soul too of all divinity (as some observe) consist very much in rightly distinguishing between the two covenants - the covenant of works and the covenant of grace; and between the two dispensations of the covenant of grace - that under the Old Testament and that under the New. Now observe, I. What is here said of the old covenant, or rather of the old dispensation of the covenant of grace: of this it is said, 1. That it was made with the fathers of the Jewish nation at mount Sinai (Heb 8:9), and Moses was the Mediator of that covenant, when God took them by the hand, to lead them out of the land of Egypt, which intimates the great affection, condescension, and tender care of God towards them. 2. That this covenant was not found faultless (Heb 8:7, Heb 8:8); it was a dispensation of darkness and dread, tending to bondage, and only a schoolmaster to bring us to Christ; it was perfect in its kind, and fitted to answer its end, but very imperfect in comparison of the gospel. 3.

— Matthew Henry's Concise Commentary (public domain)

now--not time; but "as it is." more excellent ministry--than any earthly ministry. by how much--in proportion as. mediator--coming between us and God, to carry into effect God's covenant with us. "The messenger (angel) of the covenant." which--Greek, "one which" [ALFORD]: inasmuch as being one which. established--Greek, "enacted as a law." So Rom 3:27, "law of faith"; and Rom 8:2; Rom 9:31, apply "law" to the Gospel covenant. It is implied hereby, the Gospel is founded on the law, in the spirit and essence of the latter. upon--resting upon. better promises--enumerated Heb 8:10-11. The Old Testament promises were mainly of earthly, the New Testament promises, of heavenly blessings: the exact fulfilment of the earthly promises was a pledge of the fulfilment of the heavenly. "Like a physician who prescribes a certain diet to a patient, and then when the patient is beginning to recover, changes the diet, permitting what he had before forbidden; or as a teacher gives his pupil an elementary lesson at first; preparatory to leading him to a higher stage": so Rabbi Albo in his Ikkarim. Compare Jer 7:21-22, which shows that God's original design in the old covenant ritual system was, that it should be pedagogical, as a schoolmaster leading and preparing men for Christ.

— Jamieson-Fausset-Brown Commentary (public domain)