In Oedipus the King by Sophocles, Oedipus is looking for the king's murderer. Ironically it turns out that Oedipus had unintentionally and unknowingly killed the king on his way to the kingdom some years beforehand. The most significant lines in the story come from Oedipus in his speech to the people of the city cursing the person or persons who killed the king and threatened those who knowingly hid him.
"Now my curse on the murderer. Whoever he is, a lone man unknown in his crime or one of among many, let that man drag out his life in agony, step by painful step. I curse myself as well if by any chance he proves to be an intimate of our house, here at my hearth with my full knowledge may the curse I just called down on him strike me." Here Oedipus calls the gods to curse the man who murdered the late king Laius. Again ironically Oedipus has called down a curse upon himself unknowingly. The truth begins to unfold and Oedipus" world begins to fall apart. .
The Shepard tells the story of how he spared Oedipus" life when he was the child of Jocasta, the queen and his new wife and Laius, the deceased king. Prophets told the King and queen that their son would murder Laius so they sent Oedipus off to be killed in the mountains. When his life was spared he ultimately killed his father and then became king marrying his own mother. .
The curse he called down on himself came true as his mother/wife Jocasta kills herself in shame. He was banished from the kingdom for the good of the people. This is because he has brought a famine upon his people stemming from his murderous deeds. This play by Sophocles is one filled with irony. Perhaps the largest piece of irony is the curse that he called down upon himself.