The fact that faith is required to believe in any given Holy book demonstrates that there's no evidence or proof for its claims, otherwise it would be common knowledge. This allows for a myriad of crazy and superstitious beliefs to take hold of the individual if they wish to delve into a worldview that is lacking any sort of rational explanation for things via evidence and/or reason.
"It is the mark of an educated mind to be able to entertain a thought without accepting it" ~ Aristotle
