Douglas Moo, Blanchard professor of New Testament at Wheaton Graduate School and member of the Committee for Bible Translation (CBT), expressed his struggles with the NIV’s rendering of sarx as “sinful nature” instead of the more literal “flesh.”
Case #1, according to Prof. Moo:
Whenever I taught Romans over the last couple of decades, I always criticized the NIV translators’ decision to translate sarx (flesh) when Paul uses it in a negative way as “sinful nature.” I argued that by introducing the word “nature” in these contexts, the translators were setting up a potentially serious misrepresentation of Paul’s understanding of Christian existence.
After being appointed to CBT, prof. Moo had to deal with sarx again but this time to affect a change in the NIV translation:
So the decision came down to this: Should we continue to use “sinful nature,” even though that phrase may give a wrong impression? Or should we stick with “flesh,” even though many English readers may not understand it? The committee elected to stay with “sinful nature,” at least in most places.” (“Romans,” NIVAC, p. 253)
Yes, the chances for misunderstanding are there. But I say keep “flesh” for sarx in the text and provide a footnote.
Keep “flesh” for sarx at John 1:14, though CBT might be tempted to follow the NLT, “human” in the text and “flesh” as a footnote. My suggestion is to do the opposite of the NLT.
“Flesh” for becoming human has a unique incarnational ring to it.
At 1 Timothy 3:16, “a body” for sarx is already awkward. Why not use “flesh” and then “a human body” as a footnote. That should do it.
At Hebrews 5:7, return to “flesh” instead of “life on earth” for the Greek sarx and footnote “life on earth.” Again, “flesh” has that incarnational ring to it—a ring that “life on earth” does carry.
But I don’t think these suggestion will be reflected in the NIV Bible 2011. My feeling is that sarx will continue to be translated the way it is in the NIV, at the places I’ve noted above.