I've been thinking about this lately, and the group think/herd mentality that existed back in the Bible times when it came to religion, was largely due to that there wasn't much diversity. If anyone deviated from heterosexual group think thoughts about how a community should be ''governed,'' they were shunned and put off as an outcast. Many Christians will say that the Bible's ''authors'' were all in agreement yet didn't live in the same areas, so how could it be just be random that the stories were similar? But, word of mouth, and the fact that there wasn't much in the way of diversity, and no technology at all, could easily lend itself to people all having similar thoughts about a god. ''My crops aren't growing, I must have done something wrong and God is punishing me.'' ''I've sinned, so God isn't rewarding me with children.'' On and on these groups seemed to create a god that seemed to be about reward and punishment, because that's how they lived their collective lives. So, ''God's word'' to me, seems more like people's attempts to make sense of why good and bad were happening, and once again, if you didn't agree with how they interpreted God, then you were shunned. The NT offers much more hope, and it's been thought that Jesus could have been an actual historical figure, but the story of his death and resurrection, the virgin birth, etc...it would require faith to believe it. Before the 'virgin birth' of Jesus, it was thought of in other religions, that the gods were having sex with mortals and producing 'divine' children. So, it's not that outlandish to hear the virgin story (back then) and believe it.
The fact that many people believe these stories to this day, shows that if you preserve fables and hearsay stories in a book, and create this illusion that it's 'sacred' ...it's more convincing. Plus, the Catholic Church actually was the pioneer if you will, of moving the Christian faith along, even if you disagree with the Catholic Church, that's true. Luther eventually would reveal that the RCC was abusing its authority, and then now we have all these Christian denominations, sects, etc.
So, my thought is ...it's man's word making sense of the Unknown. Calling it a god, and creating a religion to foster the group think, and control people who don't agree. And now, it's become a lucrative business opportunity. Just ask Joel Osteen about that.