The thought and theme of Oedipus Rex, a tragedy written by Sophocles, revolve around the concepts of fate, free will, and the consequences of one's actions.

The play tells the story of Oedipus, a king who unknowingly fulfills a prophecy that he will kill his father and marry his mother. Despite his efforts to avoid this fate, Oedipus ultimately brings about his own downfall through his relentless pursuit of the truth.

The play explores the idea that fate cannot be avoided, and that attempts to do so may actually lead to its fulfillment. It also raises questions about the role of free will in shaping one's destiny, and whether individuals have any control over their own lives.

Additionally, the play highlights the consequences of one's actions, and the idea that even the most well-intentioned actions can have unintended and disastrous outcomes.

Overall, the thought and theme of Oedipus Rex emphasize the complex interplay between fate and free will, and the importance of accepting responsibility for one's actions.