Prior to learning the painful truths that he has killed his father and married his mother, Oedipus thinks of himself as "Fortune's favorite child" even if, as he comes to believe, his parentage is not noble. Jocasta, his wife and mother, has sensed the truth and encouraged him to stop his quest for knowledge, but he believes she is only too proud to accept him now that he may not be noble by blood. He is wrong. When the herdsman arrives, the herdsman and the messenger piece the full story together: Jocasta gave her own baby (the son of Laius) to the herdsman, who gave it to the messenger long ago, rather than kill it. This messenger gave it to the household of Merope and Polybus, rulers of Corinth and the people Oedipus has known as his parents (who turn out to be his adopted parents). In this way, Oedipus discovers the truth and experiences a reversal of fortune. No longer conceiving of himself as "Fortune's favorite child," he realizes that he is "a wretch, in birth, in wedlock cursed, / A parricide, incestuously, triply cursed!"
Oedipus's wife and mother, Jocasta, kills herself, and he scratches out his own eyes with her brooches. Now,
He vows to fly self-banished from the land,
Nor stay to bring upon his house the curse
Himself had uttered; but he has no strength
Nor one to guide him, and his torture's more
Than man can suffer [...].
Oedipus had, before, promised to banish Laius's killer from Thebes, and he must make good on that vow now, even though it now applies to him. While he was once so high and dignified, he now suffers terribly as a result of his own words and actions. He must go, but he is blind, abhorred by all, and suffers more than one can imagine.