Playing an integral part in the play, the Chorus of Oedipus Rex, the men of Thebes, are orginally supportive, then critical, and finally, sympathethic to Oedipus. In the line cited above, the Chorus makes the critical observation that no one can escape fate, for in time Fate will find him because free will has its limitations of time and character. Thus, this line is central to the themes of Oedipus Rex.
While it is his pride and intelligence that assists Oedipus in solving the riddle of the sphinx, ironically, this pride and quick temper, his fatal flaws, are also agents of his undoing as his refusal to learn of his past allows his destruction since there is enough time for all those with this knowledge to appear and reveal the truth. Despite the warnings of Teiresias that he
...will never tell you what I know.
Now it is my misery, then, it would be yours. (316-317)
Oedipus persists until with time, his past is revealed by messengers and the shepherd.
Certainly, as the second messenger says in the EXODOS,
The greatest griefs are those we cause ourselves.(1262)
- Human free will has its limits
Despite the efforts of the parents of Oedpius, Jocasta and Laius, to prevent their son from fulfilling the prophecy about him, by their binding and leaving him out for a certain death, Oedipus is rescued by a shepherd. Later, Oedipus inadvertently encounters his real father and kills him without realizing the magnitude of what he has done. So, while he has been free to kill, Oedipus unconsciously seals his fate as he is made king of Thebes and marries his mother after Laius's death and his solving of the riddle of the sphinx that curses Thebes.
Further, despite the efforts of Oedipus to learn the truth so that he can quell the plague that torments the citizens of Thebes, he cannot change his fate that he is cursed and the cause of the plague himself. When the shepherd tells Oedipus why he rescued him as a baby,
I pitied the baby, my king,
And I thought that this man would take him far away
To his own country.
He saved him--but for what a fate!
For, if you are what this man says you are,
No man living is more wretched than Oedipus. (1113-1117)
Oedipus realizes that he has been victimized by fate and his choices have been limited since his fate has loomed over him from his birth. Above all, his ignorance of his past has prevented him from helping his subjects and even himself.