Someone asked me about this passage this morning, and I thought it was another great illustration of why we need to affirm freedom on the part of the biblical writers, as opposed to God dictating the words to them (audibly or through some sort of mysterious mind-meld). In this case, LXX and MT both have “EARS” instead of “body” in the Hebrew 10:5 QUOTATION of the OT, “a BODY you have prepared for me.” How in the world (or where in the world) did the writer of Hebrews get “body” when both MT and LXX have “ears”?  I can tell you one thing, the Spirit didn’t whisper it to him (or her, for those who like Priscilla as the author of Hebrews).  This is about as far “off track” you can get in terms of a NT author quoting the OT.  The wording is a clear alteration of the OT readings of both MT and LXX. But there is an answer.  In this PDF, Karen Jobes does a wonderful job of explaining the rhetorical technique used by the NT writer, making clear that the writer wasn’t intending to correct the OT by the word change.