This dramatic female monologue comes from the Greek play Oedipus the King, Sophocles' most famous tragedy.
Some Necessary Background Information
Queen Jocasta (Yo-KAH-stuh) is one of Greek mythology's most ill-fated characters. First, she and her husband King Laius (LAY-us) learn from the Delphic Oracle (a sort of ancient fortune teller) that their newborn child is destined to kill his father and marry his mother. So, in the play's first attempt by characters to outwit Fate, they pierce their baby's ankles to bind them together and leave the child out in the wilderness to die.
Little does Jocasta know that a kindly herdsman saves her child. The baby is called Oedipus (ED-uh-pus) - which means swollen ankles - by his adoptive parents, King Polybus (PAH-lih-bus) and Queen Merope (Meh-RUH-pee) from the nearby city-state of Corinth.
When Oedipus grows up, completely unaware that he was a “foundling,” he learns of the prophecy that claims that he will commit both patricide and incest. Because he believes that this prediction applies to Polybus and Merope, the parents that he loves, he quickly leaves town believing that he can avoid that terrible fate. This is the play's second attempt by a character to outwit Fate.
His escape route has him heading towards the city of Thebes. On his way there, he is almost run over by the chariot of an arrogant king. This king just happens to be King Laius (Oedipus's biological father). They fight and guess what? Oedipus slays the king. Prophecy Part One fulfilled.
Once in Thebes, Oedipus solves a riddle that saves Thebes from a monstrous Sphinx and therefore he becomes the new king of Thebes. Since the previous king died in an incident of ancient road rage, which for some reason no one ever connects to Oedipus, the current queen Jocasta is a widow and needs a husband. So Oedipus weds the older but still beautiful Queen Jocasta. That's right, he marries his mother! And over the years, they produce four children. Prophecy Part Two fulfilled - but almost everyone, including Oedipus himself, remains unaware of all of the thwarted efforts to trick Fate.
Just prior to the monologue below, news has arrived that the king Oedipus believes to be his father has died - and it was not at Oedipus's hand! Jocasta is exceedingly pleased and relieved, but Oedipus is still bothered by the second part of the prophecy. His wife tries to ease the fears of her husband (who is also her son - but she has not figured this out yet) in this speech.
Why should a mortal man, the sport of chance,
With no assured foreknowledge, be afraid?
Best live a careless life from hand to mouth.
This wedlock with thy mother fear not thou.
How oft it chances that in dreams a man
Has wed his mother! He who least regards
Such brainsick fantasies lives most at ease.
In another translation of the same monologue translated by Ian Johnston. (Locate Line 1160.) This translation is more modern than the one above and will help you understand the heightened language. (It's also worth looking through this version of the play for additional monologues by Jocasta.)
Many Freudian scholars have paid particular attention to this short dramatic monologue. Read up on Freud's Oedipal Complex and you will understand why.
Here is a short, animated version of the story of Oedipus the King.
This video tells the story of Oedipus in Eight Minutes.