Message in Oedipus the king?

Oedipus the King pretty much demonstrates how people cannot escape their fate. If you remember from the beginning of the play, a witch (psychic? not sure who exactly she was) explained to Oedipus' parents that their son would kill his father and marry his mother. The parents were so nervous that they abandoned the boy in the forest. However, when Oedipus grew up, he ended up killing his father and marrying his mother not knowing that he was doing so in the process. This play showed a very strange and weird example of how people cannot escape their fate. It also shows that, in Oedipus' case, that people do not always know about how their fate will turn out. Oedipus went through his life not knowing that the man he killed was his father and the woman he married was actually his mother until the very end of the play. Fate is one of the largest reoccurring examples of theme in Oedipus the King.