“Everywhere the human soul stands between a hemisphere of light another of darkness on the confines of two everlasting hostile empires- Necessity and Free Will.” Thomas Carlyle
The crucial theme in Oedipus Rex is definitely free will vs. fate. These two pathways are nonetheless intertwined. One cannot abide without the other. There will be a perpetual balance. Oedipus’s road wasn’t foggy and bleak like most.The oracle told Lais and Jocata that their son would grow up to kill his father and marry his mother. The oracle also told Oedipus his fate. He then, of his free will chose a path he thought would lead him to a different fate, but then soon realized that his own will sealed this foretold destiny.
I believe if Lais and Jocasta hadn't tried to change the situation Oedipus would have had a fairly normal life, or perhaps the Gods would have taken pity on the family's fate. The same goes for Oedipus later on in his life. If he had not left Corinth in the first place, he wouldn't have come back to his real hometown of Thebes. It's so funny that by their own free will, they sealed their fate. It was either by fear in Oedipus's case, or arrogance on Jocasta or Lais's case that this horrible fate came true.