A Body Hast Thou Prepared Me?
Many attempts have been made to reconcile the apparent discrepancy between the passages which appear in the AV as follows:
"Sacrifice and offering Thou didst not desire; mine ears hast Thou opened" (Ps. 40:6);
"Sacrifice and offering Thou wouldest not, but a body hast Thou prepared me" (Heb. 10:5).
The psalm is obviously Messianic, and Paul is using it in a Messianic dissertation. The main difference is between the phrases "a body hast Thou prepared me" in Hebrews 10, and "mine ears hast Thou opened" in Psalm 40. The Septuagint is the same as Hebrews 10:5, so it is the present Hebrew of Psalm 40:6 which is apparently faulty.
The commonest way of reconciling the two is to adopt the marginal alternative of "digged" for "opened" in Psalm 40:6, and to link this with the boring of the slave's ear who preferred to remain with his master, rather than choosing freedom as the Law allowed (Ex. 21:6), thus drawing a parallel with the willing servitude of Jesus to his Father. However, this avoids the question of why there is a disparity between the passages.
Since the apostle, writing under Divine inspiration, is quoting the Septuagint (which was commonly used by the apostles and other early Christian writers), one must conclude that the Septuagint is correct in this particular instance; and this is confirmed by Paul's reference to the "body of Jesus" in the course of his argument (Heb. 10:10).
There is an alternative explanation for the disparity between the passages, suggested originally by Dr. Kennicott and explained by Adam Clarke in his commentary on the passage. When one looks at the Hebrew of Psalm 40:6 it seems possible that the expression, "mine ears hast thou digged, has arisen due to a copying error. The Hebrew words "then a body" (az gevah) could have been carelessly copied as "ears" (oznayim), which look very similar in the Hebrew.
The passage would have then read, "mine ears hast Thou prepared". However, the words 'open' (digged) and 'prepare' are both karah in Hebrew, enabling the passage to be read, "mine ears hast Thou opened". Alternatively, the passage may have been read, "then a body Thou hast opened", causing a later scribe to opt for "ears" in preference to "then a body" in order for it to make more sense.
When we realise the great care the Hebrew scribes took in accurate copying, it seems like a bad mistake, but a faded or damaged original may have accounted for it, and thankfully such disparities are few and far between in Scripture.