How does tone, voice, and character development within Oedipus develop his ultimate downfall in Oedipus Rex?
We might argue that Oedipus' growing insistence on being told the truth, demonstrating a reckless pride, leads to his downfall.
Warned by Teiresias and Jocasta that the news he will receive if he continues to press for the truth will almost certainly be damaging. Yet, Oedipus insists. He demands that he be told the truth and implies that he is prepared to handle it, no matter what the truth holds.
This recalcitrant hubris is manifested in Oedipus' tone and demeanor.
When Teiresias refuses to answer Oedipus's call and later resists revealing the king's dark truth, Oedipus grows impatient, hostile, and abusive. (eNotes)
Though we can hardly blame Oedipus for fulfilling the prophecy, we can cast some blame on him for ruining his family. If he had taken the advice of his wife, he could have gone on in innocence (or at least ignorance), never knowing that he had fulfilled the terrible prophecy.
His pride, however, demanded that the truth come out and that he hear it.