And so the mantra is "context." What does the context of the verses say? Read what comes before and after and see how that clarifies things.
It usually does. But some sections of scripture are a bit jumbled. Take Jeremiah. The history and the collected prophecies aren't in sync.
And Exodus. Exodus 20 is of utterly different tone from 21-23, though it is written as though it is all one continuous narrative. I think you have to look back to Exodus 19:16 and not just to Exodus 24:4 "Moses wrote down all the words of the Lord"
Distinguishing isn't always very obvious. Jesus was pretty clear that some of what Moses wrote wasn't quite Plan A. He was also clear that some other parts definitely were, including an expansive reading of Leviticus 19:18 about loving your neighbor ("Who is my neighbor?")
A huge problem is that if you claim to be able to distinguish Plan A from Plan B, you invite termites to stay; and according to their several besetting sins they'll imagine warrant to dispose of rules on money or sex or whatever. There's clear enough warrant for Christians to dispose of the Levitical rules for worship, and some rules are tied to the people and the land, and some are obviously simple sanitary rules, but without a deep understanding of the rest of scripture you won't be able to escape the temptation to de-weight the uncomfortable rules. And thinking you have such a deep understanding is probably the clearest sign that you don't.
One trivial example is the "We wear clothing of different kinds of fabric; why should rules about who we have sex with be any more binding?" That kind of sloppy analysis hardly requires refuting--and it is probably just a slogan in the mouth of someone who wouldn't be persuaded no matter what you replied. (Quick reply: the second ties in with the Big 10, the first does not and is fairly obviously related to ritual purity and a metaphor for being single-hearted. OT ritual purity is not an issue for Christians, the metaphor is fine but not critical, but human relationships are the same now as then.)
More sophisticated analyses explain why charging interest isn't really charging interest, or that it isn't really bad, or that we can't avoid it so may as well give up. Renting money has certainly been an extremely powerful tool and we've reaped substantial benefits, but although correlation isn't causation, it seems to have had some some less happy side effects on the value of money over time. I'm not an economic historian, and maybe the side effects are worth it. Still.
So what's the best approach? An official Magisterium? An open bazaar, trusting that the truth will eventually prevail? Strongly urging all would-be interpreters to humbly consider the wisdom of their ancestors? That last is not a popular attitude these days, but it seems like a promising approach, provided we explain what our ancestors actually thought and don't just filter the past through the fad du jour.