To add to the superb answer above...
Fate all too often seems like some nebulous catch-all. An excuse. A scapegoat. Something unforeseen. Dramatic irony. All this commentary about "fate catching up with Oedipus," I think, is pandering nonsense.
Fate in Oedipus cannot be confused with punishment or suffering. Fate is not the Sphinx, or the plague, or suicide, or exile. This kind of analogy-making is non sequitir, faulty logic. To permit this is to negate humankind's responsibility and ability to rise above suffering. To place so much emphasis on fate diminishes the play as a whole. Fate renders the play deterministic, not a thoughtful craft at all.
Fate is only what Oedipus is thrown into, as it is with all of us: our family, our gender, our blood--that which is completely out of our control. Obviously, we cannot choose who are our parents, or what genetic abilities or handicaps they have passed on to us. For Oedipus, it was his crippled leg. He had no choice in being crippled.
The only fate sealed in the Oedipus trilogy comes when his parents decide to cut his angles and leave him for dead. This is the dark secret that sets tragedy in motion. The rest, in my opinion, is a series of choices: some good, most bad. I don't think it was fate that Oedipus killed his father or married his mother or brought the plague to Thebes or caused Jocasta to suicide or blinded or exiled himself. These were all choices he made, not the results of fate or oracles or the gods. Nothing is working behind the scenes--only Sophocles!
Yet, in the end, Oedipus takes responsibility for each of his choices. He suffers with dignity. He does not suicide, like Jocasta. In the end, he has a kind of victory over these choices, as he is given a sacred burial. Camus calls him a hero for this.
But, in the end, after Oedipus dies, his family continues to succumb to suffering and death. Were they destined to suffer? Of course not. Did they suffer from hubris? Of course. Is hubris the same as fate? Of course not. Is hubris the result of bad choices and decision-making? Of course.
In other words, fate is only that which is completely and utterly out of Oedipus' control. It is his gender, the color of his skin, hair, and eyes. It's family secrets, an inscrutable past. In particular, it's that crippled leg. I can't think of any other instance of fate that is any more crucial to the plot of this play.
Oedipus Rex is one of the greatest creations of Sophocles where king Oedipus is the protagonist who is the victim of his own fate. Generally, fate is the development of events outside a person’s control, regarded as predetermined by a supernatural power. In Oedipus Rex, fate defeats three characters Oedipus, Jocasta and Laius.
The tragedy of Oedipus is cruel twist of fate. Oedipus is the real son of Theban king Laius. His parents are informed by an astrologer that Oedipus will kill his father and marry her mother. That is why; they tie his legs and give to a shepherd to leave him on a mountain so that the beasts of mountain eat him. It is the character of fate that saves him to die.
The shepherd takes pity to him and gives Oedipus to another shepherd of other country. The other shepherd gives Oedipus to his childless king Polybus. Polybus and his wife bring Oedipus up as their own son. When Oedipus is young enough, he hears from an oracle that he will kill his father and marry his mother. He thinks Polybus his father and do not want to kill him and runs away from this kingdom and reaches his real state. It is the creation of destiny that brings him to his own country.
On the way to his country, he kills an old king and his soldiers for simple matter. Actually, this old king is his father Laius. So, here the first prediction becomes true and fate wins and defeats the trying of man.
Oedipus defeats Sphinx and becomes the king of Thebes. The people of Thebes give their queen to him to marry because their king has been killed. Here, again fate wins and defeats trying of man. Here, fate proves that no man can deny his sorrow and suffering.
To know about future anxiously, can be cause of Oedipus’s tragedy. Oedipus is anxious to know about his future. An oracle forbids him to know about his fate but Oedipus insists to know about and says to oracle.
“Since come it must, thy duty is to tell me”
Know about future too much is not a good thing; it brings difficulties for a man as William Ernest Hentey says,
“Knowing too much of your future is never a good thing”
Oedipus tries his best to deny his fate and save him from the worse sin but he fails because his destiny bounds him to do so. Oedipus fails and fate wins. So the role of fate on Oedipus is almighty.
Fate is one of the duality elements of the play. The major trope of blindness versus sight (Tiresias versus Oedipus) announces the theme of the search for knowledge. The presence of plague inspires a criminal investigation: one person’s crime has tainted an entire community. As in psychoanalysis, Oedipus undertakes a voyage into the past to discover his true nature. The riddle of the Sphinx, once solved by Oedipus, now reappears in the form of a riddle about his own origins.
The voice of the gods, the oracle is a symbol of tradition built on the conservative principles of hierarchy and order. The rise of Greek humanism in the age of Sophocles calls into question this traditional obeisance to the gods. Most cultures, even ones that champion individualism such as our own, are possessed of oracular traditions. Cultural attractions like astrology and New Age products promise knowledge of and control over the future. Institutions like the Dow index and the stock market offer the enticement of making a fortune. The oracle that sets the mold for Oedipus’s fate invites a fundamental question: does the world have to be guided by signs?
Freud studied poets in order to shape his own theories about psychoanalysis; Marx consulted the novels of Balzac. Literature offers a deep well of experience for the social sciences. The efforts of formal criticism bear out how many times we can go back to Oedipus and find something new. Few critics, for example, have bothered to consider the plight of Jocasta in the story. Was her demise fate, or did she have a choice?