Throughout the play, Oedipus is motivated primarily by the desire to discover the source of the plague and protect Thebes. This was also his motive before the beginning of the play, in solving the riddle of the Sphinx and freeing Thebes from its depredations. Oedipus is depicted as a responsible and dedicated ruler who does everything possible to look after his people. He is genuinely angry with the murderer who has brought this blight upon the city and is obsessed with discovering and punishing him.

Teiresias, Creon, and Jocasta all try to persuade Oedipus not to pursue his forensic examination. Teiresias initially refuses to say what he has seen in his prophetic visions. It is only when angered by Oedipus's accusations that he reveals the truth but, by this time, Oedipus is suspicious of the prophet's motives and does not believe him. Since he has already decided that Teiresias and Creon are plotting together, he is no more willing to listen to his brother-in-law. Ironically it is Jocasta, in her dual attempt to persuade Oedipus to pardon Creon and to illustrate her point that prophets sometimes err, who provides him with the evidence he needs to begin reconstructing his own parricide. Jocasta tries again to persuade Oedipus to abandon his search after the messenger's evidence that King Polybus, who has just died of natural causes, was not in fact his father. However, Oedipus remains implacable in pursuing his own destruction.