Perhaps the most distinctive difference between conservative and progressive (liberal?) Christians is their respective views on the authority of scripture. The spectrum, in fact, is quite wide on this issue. The most conservative folks are protective of a flattened, inerrant, and literal interpretation of scripture upon which the authority of scripture is fundamentally dependent. If one passage is shown to have its meaning outside of literality, the whole authority of every passage is compromised. This perspective, of course, crumbles quickly. It is unsustainable precisely because of the impossibility of reading everything in scripture literally. The parables, for example, and many of the psalms would be all but incomprehensible if we were to apply the same hermeneutic to them as we would an historical account. We simply cannot read scripture on its own terms if we flatten it into one genre, one line of reasoning, one text. The Bible is many texts of various genres which demand, perhaps in some places a literal interpretation, but in many many others, something other than a literal interpretation.
The other side of the spectrum promotes a much more mystical and mythical interpretation of the text. Scripture, for the most liberal Christians, is not to be taken as authoritative at all, at least not in the traditional meaning of the word. Scripture is like some art; it inspires, it is compelling perhaps, but it's not "right" or "wrong" at all. Its claims are rarely, if at all, normative--always veiled in ambiguity. Its narratives are rarely, if ever, historical in any sense. And its gospel is by no means corporeal other than in a moral sense. In other words, Jesus might want us to be good, but crucifixion and resurrection are not to be taken literally or historically. Atonement isn't a thing. I once had a Harvard grad youth leader from a liberal church, in a very dismissive tone, tell my students at a youth camp, "Jesus wasn't really the 'Son of God' nor did he 'die for my sins'" (creating a mess for me to clean up with my students). Jesus' is a story to inspire us, but not to save us in any directly supernatural sense.
Now I'm not going to pretend that I don't have sympathies for one side more than another. No one could accuse me of being the most conservative Christian... but I would equally resent the accusation of being on the most liberal side of the spectrum. I believe I have a much more nuanced perspective than can be represented exclusively by either side. Suffice to say, I believe in atonement, I'm not afraid of authority, and I believe the death and resurrection of Jesus is the exclusively salvific reality of divine and human history. But I don't believe the Bible is always to be taken literally, I certainly don't think it can be flattened into one text or genre, and I don't think its authority is dependent upon its perfection or any normatively literal reading thereof.
In short, neither the liberals or the conservatives are right (or totally wrong).
But one thing I wanna point out... and here's where I'm going to get more critical of conservatives (likely because that's the perspective that best describes how I used to think)... is that the great hypocrisy of conservativism is that while they think of themselves to be the most protective of biblical authority, it is their claim upon the authority of scripture that is the more fragile and displays the least amount of trust.
While liberals aren't too concerned with "protecting" the bible, even from fallibility, their trust in scripture seems to hold even in the face of criticism. It's no less their bible if it's got mistakes or if it turns out to say something they didn't think it said. Whereas, for conservatives, the attitude reflects that if the bible doesn't say exactly what it seems to say or if it turns out that the original intention of a pericope or passage is so contextual that it can't mean now what it used to mean, the whole thing falls apart. I once had a conservative tell me that if I didn't believe that the events described in the book of Joshua happened the way it says they happened then I couldn't possibly believe in the resurrection of Jesus. Certainly the scripture's got authority for these folks, but they've hardly got any trust in it. If those six verses about homosexuality don't mean exactly what they think they mean, then nothing in scripture can be trusted.
To trust means to be faithful, which includes obedience perhaps, but it not limited to obedience. Faithfulness, unlike a flat-footed obedience, is not contingent upon the expectation of perfection. I love my wife, I trust her, she even has authority for me (I wouldn't make a decision in life without including her and submitting myself to her and, likewise, she wouldn't make such decisions without me either), but my trust in her and my relationship with her doesn't fall apart if she makes a mistake. I'm under no pretense about her perfection. And my wife's faithfulness and trust in me, thank God, doesn't fall apart if I say something hurtful or deceptive in a moment of weakness. In other words, our love and our trust in one another goes deeper than surface commitments.
This is a little more like what trust in the authority of scripture should look like. It should go deeper than the surface... I don't believe it's going to be dishonest with us or that it's going to make a mistake (necessarily), but if my obedience to it has a foundation of trust in its authority, then it won't be any less important, authoritative, or trustworthy to me if I discover that it says something I didn't think it said or that something I thought was to be taken at face value actually turned out to be more metaphorical or contextual. If Genesis 1 turns out to be a poem, or if Joshua represents a slightly different way of recording history than the way I learned in high school (a way that was developed after the Enlightenment), I'm not going to stop trusting it. The whole thing doesn't fall apart.
And so while I certainly take issue with the most liberal readings of scripture, there is a trust displayed among liberals that's just missing in the uncompromising obedience of conservatives (though it too can be respected). If scripture is utterly rigid for you, if your relationship to it would necessarily be severed if it was metaphor or myth where you thought it was literal, ask yourself how much you really trust it. If the only truth you can glean from it is in its literality, if its sole authority is dependent upon such literality, ask yourself if it is really authoritative to you at all.