For I will be merciful toward their iniquities, and I will remember their sins no more.”
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.
Commenting on Hebrews 8:6-13
For I will be merciful to their unrighteousness,.... That is, sin; for all unrighteousness is sin, being contrary to the justice of God, and his righteous law: and the phrase is expressive of God's forgiveness of it, which is a very considerable article of the covenant of grace; mercy is the spring and original of pardon; it is what God delights in, and therefore he...
Verse 12. For I will be merciful to their unrighteousness, etc. That is the blessing of pardon will be much more richly enjoyed under the new dispensation than it was under the old. This is the fourth circumstance adduced in which the new covenant will surpass the old.