Despite the warnings from Tiresias and other characters who suggest that he is destined to commit the foretold acts, Oedipus remains convinced of his innocence. He cannot fathom that he would unknowingly kill his own father and marry his mother, as those actions go against his moral compass and self-perception.
Oedipus's stubbornness and refusal to accept the truth exemplify the tragic hero's fatal flaw in classical Greek literature. It ultimately leads to his suffering, downfall, and the unraveling of his life.