The Chorus serves as a foil for Oedipus throughout Oedipus Rex. The Chorus in Greek tragedies serves many roles, including that of narrator and ensemble. However, in Oedipus Rex they are not omniscient narrators and instead are ignorant of Oedipus's fate for much of the story. As such, the Chorus serves as a stand-in for an ignorant audience, frequently lamenting the state of Thebes and urging their king to save them from the curse of the gods. This enables Sophocles to build dramatic tension throughout the play, despite the fact that the audience already knows how the story will end. Similarly, the Chorus's shock and horror after discovering the truth of the situation and seeing a blinded Oedipus for the first time heightens the pathos of the play's climax.
At the same time, the Chorus often evokes the Greek gods and goddesses, praying for assistance and prosperity during the trying time in which the play takes place. This faith in the wisdom of the gods juxtaposes sharply against Oedipus's nearly sacrilegious disbelief in the prophets of Apollo and his prideful belief that he will be the hero Thebes needs once again. The dichotomy between the Chorus's humility and Oedipus's pride helps to illustrate the tragic hero's downfall. While the Chorus is just as ignorant of the truth of the prophecy, they also have a humility Oedipus lacks.