I once wrote an article for the Baptist Waymark titled "What's wrong with the Greek?" I don't remember exactly what all I wrote, but the idea was to urge caution in using the Greek language/New Testament to develop theologies, positions, ideas, etc. At the risk of appearing ignorant, and perhaps even contradictory, I think this is a good maxim to follow -- if you can't find it in the English, it's probably not in the Greek; don't build a theory on it. [If Spanish, French, German, etc. is your native language, place that in the place of "English" in the previous sentence].
Many people recommend using the Greek to get those little nuances and fine points that we might not get in English. And that is not unreasonable. One problem is this -- 98% of us probably don't know enough about the Greek language to get the little "nuances" and "nuggets," and in fact probably confuse ourselves as much as we help ourselves. There are some real Greek language scholars out there, but most of us (including pastors who have studied languages in seminaries and universities) are not really scholars. We know enough to get into trouble, but often not enough to get out of it! A friend on the BaptistBoard once wrote, "I always wince when I hear a preacher 'explain' the Greek or Hebrew because I don't know if he's a dime-store translator or a scholar." Exegetical Fallacies by D. A. Carson should be an eye-opener to anyone who will read it with an open mind. I end by saying that I don't discourage studying and using the Greek language, just urge that we use caution. The same thoughts could be said relative to the Hebrew language as well.