The chorus in Greek tragedies served several functions: commenting on and reacting to the plot, establishing ethical frameworks, adding spectacle through song and dance, and pacing the action. In Oedipus Rex specifically, the chorus represents the citizens of Thebes and gradually comes to understand and pity Oedipus's fate over the course of the play through their odes, guiding the audience's emotions and response. They dramatize the unfolding of events and their own enlightenment.