Oedipus is told by the gods to find the killer of King Laius. He is very diligent in the inquiry and finally comes to the horrible truth that he himself is the murderer. Jocasta kills herself at the horrible realization that she has laid with her son. As Oedipus puts out his eyes at finally seeing the truth he says "You, you"ll see no more the pain I suffered, all the pain I caused Blind in the darkness-Blind! (1011). This fulfills the final part of the Sphinx's riddle, for Oedipus will have to walk with a cane for the rest of his life because of his blindness. This will give him the 3 feet which man walks with at the end of his years.
Oedipus used his intellect and diligence to answer the riddle of the Sphinx. Many of the most intelligent young men of Thebes had been killed attempting to answer the riddle but Oedipus proved his intelligence superior to theirs. Oedipus uses the same intelligence and perseverance to find the killer of Laius. He does not give up his search even when Jocasta warns him to stop and let the matter rest. He calls the shepherd and interrogates him until he discovers the horrifying truth that he is the killer. Oedipus's intelligence was ultimately his fatal flaw. .
If Oedipus had not been as courageous he would have never ventured to answer the riddle of the Sphinx. Thus, even though he had killed his father, he would have never becomes king of Thebes and laid with his mother. In addition, if Oedipus had had the courage but not the intelligence, the Sphinx would have killed him for answering the riddle incorrectly. Sophocles used this to characterized Oedipus as a tragic man for he came about his tragic discovery not because of an evil act or an evil trait, but because of the person he was. Oedipus" traits, which ultimately gave him riches and power, led to his tragic ending. Also, the god Apollo did not predestine that Oedipus would kill his father and marry his mother by the oracle; he only stated what he knew was inevitable because of who Oedipus was.
