D&D 3.0: Tales from Mystara
The precepts of the Peoples Temple are based on the Hope Stones, three pieces of stone that were inscribed by its founder with magical powers. Raising the dead, seen the future and vanishing demons were the three powers attributed to the stones.
Other depictions of the Hope Stones are that there are 10 of them and that they are shaped like the 10 Ierendi islands, and carved with hieroglyphs. The carvings are rumored to be fragments of a powerful epic spell or maybe more than one.
Another story is that the carvings on the stones are instructions to find a long lost treasure.
The original stones are believed to have long since been destroyed.