It is clear from the way that prophecies are repeatedly referred to throughout the text, and that Teiresias, an important prophet, is a prominent character, that fate is a key theme of this play. Consider the time and energy that Jocasta spends trying to convince Oedipus that he can safely ignore the prophecy that points towards his own involvement in the death of the former King of Thebes, who turns out to be his father. She deliberately mocks fate and argues that prophecies are not to be listened to. Note what she says to Oedipus to assuage his fear and worry about the prophecy that he killed Laius:
Then thou mayest ease thy conscience on that score.
Listen and I'll convince thee that no man
Hath scot or lot in the prophetic art.
The story of her own dead child is an attempt to prove that the original prophecy of the son of Laius ending up killing him is false, and that "no man" is the victim of fate, yet of course the tremendous irony of the text is precisely the opposite: Oedipus is a victim of fate, and it is his own determination to unearth the identity of the murderer of Laius that leads to his own discovery of the truth of the prophecy and his own identity. Fate is shown to be an absolute reality that cannot be altered or changed, no matter how hard Jocasta tries to convince her husband otherwise. However, when the audience bears in mind how much Jocasta has to lose were the prophecy to be proved true, perhaps her persistence is understandable.