While perusing another atheist blog, I came across a good comment by the blog owner, PhillyChief, which I have partially quoted below (I'm only quoting the relevant portion to what I want to talk about today):
...The horrors we see today in Islam were once true of Christianity, the stoning, torturing and so forth of blasphemers and non-believers. Did the Bible change? No. Did society? Certainly. At one time the Bible was used to justify white supremacy, slavery, imperialism, and denial of women equal rights. Again, did the Bible change? No.
The obvious Xian rejoinder to this is that this is a strength of the Bible, that it is truth and therefore does not need to change. It is us that need to change in order to come more in alignment with what the Bible says. There are multiple problems with this however.
First, the obvious response is to ask why god couldn't be more clear from the beginning. Imagine the amount of suffering that would have been avoided had people been able to read the Bible and discern right from the start that slavery is bad, that denial of equal rights to women or anyone else is bad, etc. Simply by writing a better book, god could have spared a lot of people from needless suffering and injustice.
Second, this is an obvious capitulation to the fact that morality evolves over time and within society. Apart from the special pleading and post-hoc reasoning in going back and asserting that our current understanding of morality is what the Bible obviously intended, we are left with a situation where we determine our own morals as a society and then input it back to the Bible. IOW, the Bible becomes a superfluous document and we are left to fend for ourselves and develop our own moral codes. There's no longer any reason to hold the Bible up as a moral guideline, since even if it did come from god and holds absolute and absolutely good morality, we as a society are still left to figure out for ourselves what is or is not moral.
Once again, we see the Xian caught in a bad spot. It's undeniable that our morals have changed over time, while the Bible hasn't (minus copying and textual errors that we know have propagated over time). The logical conclusions of this are not so good for the Xian.