Misuse of Romans 3:22-26
There is perhaps no passage in the bible that is less clear in meaning than Romans 3:22-26, and I think more ink has probably been dedicated to this passage than any other.
The meaning of every single phrase in Paul's ridiculously long sentence has been seriously contested among scholars. The passage is made up of a long series of prepositional phrases and it is unclear how these are supposed to be interacting with each other. The passage is also packed with important individual words such as "sin", "righteousness", "faith", "grace" which I would guess have been the sole topic of at least one hundred books each. The question of how to translate "propitiation"/"expiation"/"sacrifice of atonement"/"mercy seat"/"conciliation" has also had a ridiculous amount of ink spent on it. The recent controversy over how to translate "faith of Christ" which has spawned dozens of journal articles seems to be simply the icing on the cake.
Because of the total scholarly confusion over the passage, no one has much of an idea how to translate it. Or rather, everyone has ideas but they're all different to each other. Since the passage itself is so unclear and ambiguous, translations and interpretations of it have to be guided by a person's wider theological views. Thus what we get in translations of it is generally a clear statement of the translators theology (or their best guess at Paul's theology), rather than any worthwhile translation of the Greek. Our English translations also have a nasty habit of copying each other when it comes to difficult passages, so generally our bibles render pretty much wholesale the King James translators' guesses.
Now when it comes to using this passage in order to interpret and understand Paul's theology, I am reminded of Augustine's view that we should interpret the difficult passages in light of the clear ones and not vice versa. The thing therefore that causes the most trouble is that the passage looks clear in English. The translators have done a great job of rendering unclear Greek into crystal clear English. This has the unfortunately result that the unsuspecting English reader can think they see in this passage the clearest possible statement of their theology and start using it to interpret other passages.
So whenever I come across a theological argument which starts off by citing Romans 3:22-26 to prove its point, I smile and sit back and mentally change gear knowing I'm reading theological fantasy.