Albert Barnes on Hebrews 10:6

In burnt offerings and sacrifices for sin thou hast had no pleasure. This is not quoted literally from the Psalm, but the sense is retained. The reading there is, "burnt-offering and sin-offering hast thou not required." The quotation by the apostle is taken from the Septuagint, with the change of a single word, which does not materially affect the sense--the word ουκευδοκησας ouk eudokesas-" thou hast no pleasure," instead of ουκηθελησας ouk ethelesas "thou dost not will." The idea is, that God had no pleasure in them as compared with obedience. He preferred the latter, and they could not be made to come in the place of it, or to answer the same purpose. When they were performed with a pure heart, he was doubtless pleased with the offering. As used here in reference to the Messiah, the meaning is, that they would not be what was required of him. Such offerings would not answer the end for which he was sent into the world, for that end was to be accomplished only by his being "obedient unto death."