PATMOS, Greece — It’s 3:45 a.m. on a Saturday and I am outside the Holy Monastery of St. John the Divine, wondering if my invitation to join the monks in an overnight prayer service will be honored. The locked gates to one of the world’s most revered holy places are themselves imposing, looming high above the port of Skala on this island in the eastern Aegean.

Little do I know that before the night is over, I will be on the receiving end of an apocalyptic prophecy.