Here's the problem with predictions in the Bible. They are all self fulfilling. The old treatment had been around a long time. There were also many many of these "prophets" running around trying to out prophet each other. It's extremely likely many of them knew all the predictions by heart. Add in a little survivorship bias, and bam you have a religion.

An easily studied recent example is Scientology, a book writer created a new religion on a party bet. It's now how big?