My humble contribution:
All authority needs some sort of clout to enforce "rules" of conduct. Parents spank (or otherwise punish), governments imprison or behead. Religious leaders - not wanting to be left out - had to come up with something equally threatening.
It becomes especially difficult if the rules you are trying to enforce are ambiguous and infractions easily hidden. (Maybe the King can't see what goes on in your bedroom, but God can!) The resulting punishment is invisible as well, tucked safely away in an afterlife nobody comes back to tell about.
Almost all cultures have some sort of invisible club to hold over the heads of believers, whether it be Armageddon, Hellfire, or coming back in the next life as a sofa cushion in Opra Winfrey's house.
As to the Bible being ambigous, I can't imagine why I thought it was perfectly lucid when I was a devoted Dub. Reading it now is almost like trying to apply Nostradamus to modern times: the words are flexible enough to mean just about anything. This is especially true when Bible thumpers try to make it prove the Trinity, Immortality of the Soul, Hellfire, or that Geriatric Sexist Pig Bullies are the Faithful and Discreet Slave.
I'm with you, Ona. I would flip a middle finger to any deity who would torture people eternally.
Wasa