Hebrews 6:20
Hebrews 6:2020where Jesus our forerunner has entered on our behalf. He has become a high priest forever in the order of Melchizedek.
— Jesus "has become a high priest forever in the manner of Melchizedek" — sits awkwardly with Watchtower Christology because the verse insists on the forever of Christ's priesthood. The JW reading typically affirms Jesus as high priest while leaving unaddressed how a being who reverted to angelic spirit existence (Michael) fulfils the requirement of that the high priest share his brothers' nature in all respects.
introduces the Melchizedek argument that runs through chapter 7. The Aaronic priests served until they died and were replaced; Christ's priesthood, like Melchizedek's, is "without beginning of days or end of life" (7:3). The "forever" is not honorific — the chapter's argument depends on Christ's unending human-natured priesthood being the contrast that makes the Aaronic system obsolete. Pair with ("he is always alive to plead for them") and 2:17 ("had to be made like his brothers in all respects"): forever, alive, fully man. A non- human Jesus cannot fulfil this priesthood; a no-longer-active Jesus cannot intercede now. The Melchizedek argument requires the Christ Christianity confesses — the Son who took true humanity and lives in it forever.