Chizuk Emunah (Pt 2) Under the Microscope: Chapter 98

Hebrews 10:5. Referring to Psalm 40, Paul states. "Wherefore when he cometh into the world, he saith, Sacrifice and offering thou wouldst not, but a body thou hast prepared me." The quotation is erroneous. The Psalmist says, "Sacrifice and offering thou wouldst not, mine ears thou hast opened; burnt offering and sin offering thou didst not desire." The Psalmist expressed by this, that obedience to God is the chief duty of man, and that listening to Him is better than an offering, and hearkening to Him "is more acceptable than the fat of rams."

That pious feelings, and not mere ceremonials, were the essential requisites, we have already demonstrated in the First Part of this work. 

 Nobody disputes that righteousness is more important to God than ritual observance, except for the rabbis, of course! Rabbinic Judaism has perverted this, by stating (for example) that if you are in a situation where you have to either eat a bug or cheat on your taxes, it is the lesser evil to cheat on your taxes. This ruling, supported by all major authorities on Orthodox Jewish Law, is a perversion of God's intent.

From the Septuagint passage:
θυσίαν καὶ προσφορὰν οὐκ ἠθέλησας ὠτία δὲ κατηρτίσω μοι

From Hebrews:
θυσίαν καὶ προσφορὰν οὐκ ἠθέλησας σῶμα δὲ κατηρτίσω μοι

So clearly, the author is not quoting the Septuagint, although the quote is only different in one word. The word "ears" has been replaced with "body." So what is going on here? 

According to A. Lukyn Williams, the author of Hebrews is using the Alexandrian reading of the text, which uses "body" instead of "ears."

But the Jews of Alexandria did not translate "Mine ears hast Thou opened," but paraphrased, "A body didst Thou prepare for me." Why they did so is not clear, but in all probability they were moved by the desire to make the meaning of the Psalmist plainer than ever, and to leave no loophole for the reader to escape from the clear duty of consecrating himself to God wholly and entirely. They wished him to understand that God formed not his ears only, but all his body, with every one of its members, that he might hear, see, think, and perform the will of God with all his powers. If so, we must say that this old Jewish rendering is certainly interesting, and is only so far wrong that it ceases to be a literal translation, and becomes a paraphrase. But this is very common elsewhere, both in the Septuagint and in the Targums. No blame can be attached to the Alexandrian translators on this score.

The author of Hebrews is using the Alexandrian understanding of the text and making an object lesson out of it. Hebrews 10:1 connects this idea with Plato's Allegory of the Cave.

In Plato's allegory, people are strapped to a wall, only able to see shadows of things on the wall. To them, the shadows are all of reality. One day, a man is freed from his bonds and sees what objects are making the shadows, and the fire that gives them their light. The man exits the cave and sees the world for what it is. This is both the plot of the Matrix, and also a lesson from Plato.

People think that the material world we experience is the ultimate reality, but it is only a shadow of the ideal forms, which constitute the true reality. The author of Hebrews is arguing that the Mosaic Law is like the shadows on the wall. They are real, but only constitute an image of the world perfected by Messiah. In a sense, rabbinic tradition agrees with this, so long as you do not believe that Messiah is Jesus, because that is unacceptable, because the rabbis decreed it so!