The quote "Teiresias, these are the threads of destiny the gods themselves have spun" comes from Homer's epic poem "The Odyssey." In this scene, the hero Odysseus has traveled to the underworld to speak to the blind prophet Teiresias, seeking advice on how to get home to Ithaca.
The quote refers to the idea that the destinies of humans are controlled by the gods. In ancient Greek mythology, the gods were believed to be all-powerful and to have control over the fates of mortals. The "threads of destiny" are a metaphor for the fate or destiny of a person, which the gods are believed to control and direct.
The metaphor of the "threads" suggests that the destinies of individuals are intricately woven and interconnected, much like the threads of a tapestry. The idea is that every individual's fate is woven into the larger tapestry of the universe, which is ultimately controlled by the gods.
So, in this quote, Teiresias is essentially telling Odysseus that his fate has been determined by the gods and that he must accept his destiny and fulfill the role that the gods have set for him. This idea of fate and destiny plays a significant role in "The Odyssey" and is a central theme throughout the poem.