How would Sophocles's Oedipus the King have invited its original audience to respond?

One thing that this play makes quite clear is that one cannot presume to oppose the gods or go against their will.  The pride that prompts Oedipus to think that he can outwit the gods is ultimately the tragic flaw that leads to his undoing.  The audience, through Sophocles's use of dramatic irony, would certainly be encouraged to participate in his final realization of this fact. 

When Oedipus visited the Delphic oracle, she'd told him that he would kill his father and marry his mother, and so he determined never to go home to Corinth so that he would not be able to fulfill this prophecy.  Though the oracle is believed to be the voice of Apollo, Oedipus thinks he can somehow avoid the fate she spoke of.  He was wrong.  In attempting to distance himself from his parents, he actually brought himself closer to them because he didn't realize that he'd been adopted.  When he tries to prove the gods wrong, he enables the prophecy to come true. 

Oedipus refuses to hear the truth because he thinks that he knows best, even when he sends for the blind prophet, Tiresias, a seer who also has a direct connection to Apollo.  Sophocles's audience would already be familiar with the fate of Oedipus, but through his use of dramatic irony -- when the audience knows more than the character -- he successfully builds tension through moments like these.  We know the truth, but Oedipus does not, and we are encouraged to judge him for his pride, for his unwillingness to listen to those, like Tiresias or even his wife/mother, who warn him.  In the end, Oedipus cannot best the gods, and their power is confirmed.  Because of Oedipus's terrible pride, the appropriate audience response is, perhaps, to pity him but also to recognize his tragedy as the result of this flaw and to realize, with him, that the gods are more powerful than we are.