“The Bible is really clear about usury,” Stephen Stetson, policy analyst at Alabama-based advocacy group Arise Citizens’ Policy Project, tells Consumerist of the high interest rates that are a hallmark of payday loans.

That’s from Ashlee Kieler’s fascinating, and encouraging, report: “Faith V. Greed: The Battle Between Faith-Based Organizations and the Payday Loan Industry.”

As a general rule, it’s best to avoid saying anything along the lines of “The Bible is really clear about X.” The Bible is large. It contains multitudes. It’s a diverse collection of ancient writings collected over many centuries and, as such, it tends not to be as “really clear” about much of anything as some people might want it to be.

That’s not to say that the Bible is lacking in clarity. The problem, rather, tends to be a surfeit of clarity. If you turn to the Bible looking for an unambiguous, definitive and categorical statement on almost any given point, you’ll likely find one. That would solve your problem … until you realize that you can find more than one, and that they’re not all the same.

This is the trickiest, most troublesome kind of ambiguity. It’s relatively easy to deal with a single vague statement that might be open to more than one possible meaning. We have a good set of tools for handling that kind of ambiguity. But it’s a much tougher situation when we’re confronted with multiple statements that are not vague — statements that do not seem to be open to more than one possible meaning, but which do not all say the same thing.

That is the kind of ambiguity that the Bible often presents us with, and that is why it’s almost always unwise to say “The Bible is really clear about X.” It may be true about X. But it’s quite likely just as true about Not-X.

Thus for countless topics, appeals to what “the Bible clearly says” will be of no help. Slavery is perhaps the most famous and consequential such dispute. For centuries here in America, one group of (white) Christians argued that “The Bible is really clear in permitting slavery.” And they were right! They could point to a host of biblical passages and stories that unambiguously supported that claim.

At the same time, though, another group of Christians argued that “The Bible is really clear in condemning slavery.” And they were also right! They could also point to a host of biblical passages and stories that unambiguously supported their claim.

We could point to innumerable examples for which this is also true. “The Bible is really clear” about both commanding and prohibiting killing. Or divination. Or polygamy. We could marshal lists of biblical passages that unambiguously prohibit all of those. And then we could turn around and list a whole other set of biblical passages that command them, or that show God rewarding those who practice them and punishing those who fail to do so.

This isn’t just the case for obscure ethical matters or for things we might regard today as archaic or esoteric. “What must I do to be saved?” remains a central and essential question for Christians today. The Bible offers a “really clear,” definitive answer to that question. And then another one. And then another one, and on and on. And those definitive answers are not all the same and not at all easily reconcilable with one another.

And but so, my point is that you should almost never say, as Mr. Stetson of Alabama does above, that “The Bible is really clear about X.”

Almost never. But Stetson has found one of the very few exceptions to that rule. He is, in this particular case, quite right: “The Bible is really clear about usury.” This is a subject about which the Bible offers a host of clear statements all pointing in the same direction. Usury is categorically condemned throughout the many books of the Bible, and if you go looking for counter-examples where the Bible permits or praises it, you’ll come up nearly empty (I can think of a few strained examples, but none that seems wholly unambiguous).

So yes, usury is one thing about which we actually can say, as Stetson does, that “the Bible is really clear.” The Bible prohibits usury. Period.

It’s interesting, then, that this biblical clarity does not translate into Christian teaching, belief, practice or politics. “The Bible is really clear about usury,” but nearly every Christian, church, denomination, etc., clearly takes the opposite position from what the Bible really clearly says.

C.S. Lewis discusses this in American evangelicals’ second-favorite book, Mere Christianity:

There is one bit of advice given to us by the ancient heathen Greeks, and by the Jews in the Old Testament, and by the great Christian teachers of the Middle Ages, which the modern economic system has completely disobeyed. All these people told us not to lend money at interest: and lending money at interest — what we call investment — is the basis of our whole system. Now it may not absolutely follow that we are wrong. Some people say that when Moses and Aristotle and the Christians agreed in forbidding interest (or “usury” as they called it), they could not foresee the joint stock company, and were only dunking of the private moneylender, and that, therefore, we need not bother about what they said. That is a question I cannot decide on. I am not an economist and I simply do not know whether the investment system is responsible for the state we are in or not. This is where we want the Christian economist. But I should not have been honest if I had not told you that three great civilizations had agreed (or so it seems at first sight) in condemning the very thing on which we have based our whole life.

Awkward, that. Here is something we can unambiguously say that the Bible unambiguously condemns — without exception, without excuse, without a bit of wriggle room. And it turns out this is “the very thing on which we have based our whole life.”

This is a far more difficult problem for evangelical Protestants than it is for other branches of Christianity or for Judaism. Those traditions have traditions, but we pretend we don’t. “Sola scriptura!” we claim, but relying solely on scripture won’t allow us any way to justify our savings accounts, credit cards, endowments, student loans, mortgages, insurance policies or market economies.

So how do we justify those things? How do we explain or reconcile having our societies, institutions and households centered on something “the Bible is really clear about” condemning?

The explanation for that is complicated. Or perhaps the explanation is simple, but our efforts to avoid acknowledging the simplicity of it are complicated.