In a previous post discussing some of the biblical evidence for an ordained, ministerial priesthood in the New Covenant, I discussed the common claim that Heb 7:24 means that only Jesus can hold the Melchizedek Priesthood, showing that the term απαραβατος does not have the sense of "non-transferrable" but instead means "permanent" (cf. this post on David Allen's comments on this verse). I would like to add the following entry from Kittel's 10-volume lexicon as further evidence against the common Protestant interpretation of this verse:
απαραβατος
This is a rare word found only in later Gk. Only very infrequently does it have the sense of "inviolable." Epict. Enoch .. 51:2 νομος απαραβατος also P. Ryl., II. 65 18: P. Grenf., I. 60, 7. its usual sense is "unchangeable," "immutable." In this sense fate is said to be unconditionally fixed and subject to no change or alteration. Plut. De Fato 1 (II.568d): η ειμαρμενη λογοσ θειος απαρβατος δι' αιτιαν ανεμποδιστον; De Plactis Philosophorum. I. 28,4 (II, 885b): οι Στωικοι ειρμον αιτιων, τουτεστι ταξιν και επιουνδεσιν απαραβατον; M. Ant., XII, 14, 1: αναγκη ειμαρμενης και απαραβατος ταξις . . . In the sense "unchangeable" the word is a tt. in law. A judgment from the 1st cent. A.D. (P. Ryl., II, 65, 18) ends with the words: και ταλλα τα δι' αυτη[ς δι]ωρισμενα μενειν και απαραβατα ("valid and unalterable") . . . Hb. 7:24 says of Christ that because He remains to eternity He has an unchangeable and imperishable priesthood. Instead of the pass. "unchangeable" many expositors suggest the act. sense "which cannot be transferred to another": "Christ has a priesthood which cannot be transferred to anyone else." This is a natural interpretation and yields a good sense, but it does not really fit the context. We should keep to the rendering "unchangeable," the more so as the act. sense is not attested elsewhere. (Gerhard Kittell and Gerhard Friedrich, eds. Theological Dictionary of the New Testament [10 vols.: trans. Geoffrey W. Bromiley: Grand Rapids, Mich.: Eerdmans, 1967], 5:742-43)