The Cosmic Throne Becomes the Throne of Grace
“Our subject is the divinity of Christ, not his humanity, and so here I merely mention the way Hebrews portrays Jesus as the high priest who can fulfill his ministry only by sharing fully the human condition, becoming like his brothers and sisters in every respect, tested in every respect through suffering and death, so that he understands human weakness and now, from his heavenly throne, exercises mercy and grace to sinners. What is perhaps less well recognized is the connection between lordship (the subject of chap. 1) and high priesthood (the subject that chap. 2 begins to treat) that the author achieves by his use of Ps. 8.
The latter is used to show that it is only through incarnation, humiliation, and everything it means to be mortal humanity that the Son could attain to his eschatological lordship over all things. This is because his lordship is exercised for the sake of his human brothers and sisters. It is now no longer simply the sovereignty he shared with his Father from eternity, but now a sovereignty exercised in human solidarity with humans. The cosmic throne is now also therefore the throne of grace that sinners can approach with boldness (4:16). So the high priestly work of atonement is the way in which he comes to exercise his sovereignty in the the way that he does — salvifically.”
[Richard Bauckham, “The Divinity of Jesus Christ in the Epistle to the Hebrews,” in Bacukham, ed., The Epistle to the Hebrews and Christian Theology, 26–27]