Once you’ve neutered Scripture by telling it what it’s allowed to speak to us about—faith and practice, for example, but not science; sin and redemption but not history—you’re on a slippery slope.
But when a professing Christian writes
Does the saving power of Jesus vanish if sin becomes something that developed through natural history, rather than appeared all at once in the Garden of Eden?
…then he’s done. He’s not thinking Christianly in any meaningful sense. He’s no longer on a slippery slope; he’s jumped off a cliff.
If the Bible can’t tell us how sin entered the world, what can it tell us? Why must we believe in the “saving power of Jesus” if the Bible can’t be trusted to tell us what we need to be saved from?
Wiser Time 
Keep in mind, in his thought he isn’t doing away with Scripture; Dr. Gibberson believes sincerely that he is interpreting the literature in Genesis according to its type of genre (or at least that’s my impression). If he’s right, then he isn’t even on a slope–he’s just practicing sound exegesis.
(Full Disclosure: I hold to a concrete Adam & Eve, but I have a few Tim Keller-esque ideas about how that still works with evolution. I personally don’t think that Genesis allows for a symbolic reading of the whole of Genesis 2-11, though Genesis 1 is obviously poetry and should be interpreted accordingly.)
Yes, but my point is that his approach to Scripture places him as the judge over Scripture. He gets to decide what “the big point” is, and then sweep away details that he finds “fanciful.” So he gets to read Gen 3 and decide that the whole talking-snake thing is no good, but the presence of sin itself is true, and that’s the point of the story.
I’m glad he believes in “the saving power of Jesus,” but my point is that he believes that because he wants to believe it, not because it’s in the Bible. Genesis is just as much a historical narrative as John; there’s no reason to take the Resurrection literally and not Eden.* It’s arbitrary, based on what he finds acceptable to believe. I’m glad he believes in a physical resurrection (assuming he does); I’m just saying he’s abandoned any logical reason to do so.
*I’m sure you disagree. But if the first few chapters are poetic, where’s the break? Where do we shift from poetry to historical narrative? There’s nothing in the text that changes. And I picked John because, like Genesis, it is very theological and written with a literary bent. But nobody who believes it thinks that means it’s not to be taken as historical narrative.
Actually, I do agree with you on Adam and Eve, I had said so before when I replied above. I think the “break” from poetry to historical narrative happens at the end of the creation poem in Genesis 1–there is an obvious, concrete shift in the form of the literature itself. Nothing about Genesis 2 onward suggests that it is meant to be taken symbolically as a whole. So it’s good to ask, “where’s the shift?” We have to stop somewhere.
Sorry, I made that look like you don’t believe in a historical Adam & Eve. That wasn’t my intent. I just meant that you’d disagree that “Genesis is just as much historical narrative as John,” because you see a *greater*genre shift than I do. Where you place that shift is a lot safer than Gibberson’s approach– he seems to be willing to throw out whatever seems unreasonable to him.
I would suggest that even discussing the concept of sin with such language as “develop” further obscures his thesis. Perhaps I need context, but it would appear that for Gibberson, sin had some kind of qualitative and quantitative evolution (pun intended). This brings up questions like: was the first iteration or manifestation of sin less incriminating or offensive to God as the sin of today?
Don’t pretty much all of us set ourselves up as judges over Scripture? I mean, even the most literalist Christians ignore some of Levitical law.
Everyone make mistakes and they sin but we are not the one to judge their action. Like this I was told and also this is what the Bible says.