This becomes even more evident when another priest arises in the likeness of Melchizedek, who has become a priest, not on the basis of a legal requirement concerning bodily descent, but by the power of an indestructible life. For it is witnessed of him,
“You are a priest forever,
after the order of Melchizedek.”
For on the one hand, a former commandment is set aside because of its weakness and uselessness (for the law made nothing perfect); but on the other hand, a better hope is introduced, through which we draw near to God. (Hebrews 7:11-19 ESV)
If we only see Christ as priest after the model of Aaron and all other Levitical priests, then we have missed the full
scope of His ministry. Yes, His sacrificial, atoning work is everything that the Law required and foretold. However, we all stood in need of not only forgiveness of sins and the cancellation of a legal debt to God that we could never repay, but we also needed to be declared righteous and given the power to live in holiness.
To capture all of this, to paint this big enough, to portray the greatness of Christ, God had to say look at Melchizedek the king and priest. As Michael Horton puts it so well, “Jesus’ priesthood does not, therefore, begin at Golgotha, but from eternity to his incarnation, life and death, all the way to his present intercession in glory. His priestly life is referred to as his active obedience (i.e., actively obeying the entire law), distinguished from his passive obedience (i.e., suffering at the cross). In short, Christ is our priestly Savior by offering both the lifelong ‘living sacrifice’ of praise and thanksgiving and by offering himself as the guilt sacrifice for our sins. He was not only a nontransgressor of the law but the joyful fulfiller of all righteousness. His commission was to bring not only forgiveness of sins but also that positive righteousness that God wills for us and his world—and beyond even this, the confirmation in that righteousness, peace, and blessedness of which the Tree of Life was the sacramental sign and seal” (Horton, The Christian Faith: A Systematic Theology for Pilgrims on the Way, 490).
This brings us full circle from the sin and condemnation we all stood in, through the atoning work Christ’s cross and the faith to believe, to the place of being at peace with God the Father as He adopts us into His forever family with the promise that He will in the coming ages show the immeasurable riches of his grace in kindness toward us in Christ Jesus (Ephesians 2:7). All of this is made possible because Christ is a mediator of a different sort. He is not one of the Levitical priests who could only point people to the commandments, encouraging them to obey. Through His indestructible life, Jesus is now able to give that same life and righteousness to those who believe. It is a work from the inside out. And as Hebrews 7:25 puts it: "... he is able to save to the uttermost [completely] those who draw near to God through him, since he always lives to make intercession for them."