A Proposed Interpretation of Hebrews 9:15-22

Why does the author of the Letter to the Hebrews, in the midst of his rigorous argument regarding the New and Old Covenants (diatheke), introduce the rough analogy of a will (diatheke) or does he? The common interpretation understands Hebrews 9:15-22 as an analogy made between a biblical covenant and a will; I briefly contend here that better sense is made of the text if we read diatheke as a covenant between God and man—not a will.