Write about the best and worst religious traditions, observances and events you’ve ever been a part of, and write until you can somehow connect the two.
Does this become an essay about your own Bar Mitzvah mashed up with the time you accidentally knocked over a Virgin Mary statue? A miracle you experienced superimposed over the story of the time a pamphlet-wielding person came to your door in the middle of a fight with your spouse? Your Easter ham versus the time you tried gefilte fish? Whatever it is, that part is up to you, but write until you not only connect the two experiences, but see if there is a broader comment to be made about life, meaning, sacredness or something else entirely once the two events are connected.