In Greek mythology, the idea of prophecy plays a crucial role as it often serves as a guiding force for characters and plot development. Prophecies frequently foreshadow events, leading heroes on quests and shaping their destinies. The concept emphasizes the tension between fate and free will, as characters grapple with trying to fulfill or evade their foretold destinies. Figures like Orpheus and Oedipus illustrate how prophecies can be both a source of foresight and a catalyst for tragic outcomes, reinforcing the narrative's depth and complexity.