I've been doing a little research into different religions' systems of afterlife, and I cannot quite pinpoint where the popular (Christian) idea of hell originated, in as far as a place that is (A) Eternal and (B) Suffering. The neighboring/influential/parent faiths either seem to have a neutral "bad" afterlife or a suffering one that is temporary, such as Jewish Sheol or the GreecoRoman underworld, if the afterlife is even a concern at all.