The superstition about Jewish people committing blood rituals shows how far back in history anti-Semitism goes. Elijah was a messenger and a prophet who advocated for worshipping Yahweh, the Hebrew God, over other local deities. Doors are an important part of the symbolism of Passover. In this passage, Yolen incorporates that symbolism into the plot of the book, with the door being the portal through which Hannah accesses the past.