Hebrews 10:10 → Psalm 40:6

Psalm 40:6 voices a Davidic critique of sacrifice-without-obedience: "Sacrifice and offering You did not desire, but my ears You have opened... Burnt offerings and sin offerings You did not require." The LXX renders the metonymy of the opened ear (the organ of obedience) as the prepared body (the instrument of obedience) — sōma de katērtisō moi, "a body You have prepared for Me" — and this is the very form Hebrews quotes at 10:5 and places on the lips of the incarnate Christ. The present pair is the downstream echo within Hebrews' own argument: when the author concludes, "by that will, we have been sanctified through the sacrifice of the body of Jesus Christ once for all" (10:10), the "body" of v. 10 is the very sōma of the cited psalm in v. 5 — the author's keyword (sōma) carries the citation forward into its application. This is Echo, not a fresh quotation: the explicit citation stands at 10:5-7, while v. 10 reuses its load-bearing term to name the thing accomplished. The road to Christ runs by Promise-Fulfillment rather than typology (anti-default): the prepared body is not a David-figure that prefigures Christ but a first-person prophetic pledge of willing-obedience-in-body that finds its literal realization in the Son's incarnate, once-for-all self-offering — the announced "I have come to do Your will" enacted in flesh. The Levitical repetition the psalm relativized is thereby surpassed, not merely paralleled (the Contrast/typological-inadequacy register). The telos: the body the Father prepared was prepared for this — that we might be sanctified by it once for all; the willing-obedience of the psalm is no distant pattern but the Son's glad delight ("I delight to do Your will"), so that the believer beholds in the offered body of Christ not a transaction merely completed but a Savior whose joy in the Father's will is the very ground of our holiness — and beholding, is drawn to desire and rest in Him.