Epigraphs are like little appetizers to the great entrée of a story. They illuminate important aspects of the story, and they get us headed in the right direction.
And God caused him to die for a hundred years, and then raised him to life. And God said, "How long hast thou waited?" He said, "I have waited a day or part of a day."
Qur'ān, 2:261
No one's confused about how this quotation applies to the story: guy who is dead/almost dead experiences a weird time-warp. Got it.
Borges was fascinated with the idea of condensing big concepts into short stories – he didn't see much point in writing lengthy novels. (We'd love to see him have a chat with Ayn Rand.) What's really cool is that here, he manages to explore the same idea about the subjectivity of time three times in smaller and smaller forms: once in the story, once in the play-within-the-story, and once in the epigraph. Pretty, cool right?
But Shmoop still thinks there's something a little strange about this. In a story about the persecution of a Jewish writer in World War II-era Europe, Borges chose an epigraph from the Qur'ān, the holy book of the Muslim faith. Curious, right? Well, here's what we think: using diverse references really makes the abstract ideas that he deals with in his story seem more universal. Borges is all about the universal, so we're sticking with that.
P.S. Borges was extremely well-read in the realms of world literature and religion, so it's not unusual for him to make a reference like this. Take a look at some of his other works and see if you can find similar references. We dare you.