In Antigone by Sophocles, the Chorus, which consists of a group of Theban elders who are advisers to King Creon, performs three important roles. First, they provide information about what takes place offstage, filling in backstory or action that is necessary for the audience to understand the plot. For example, at the beginning of the play, they explain the battle that recently took place, where Eteocles and Polynices, Antigone's brothers, faced off for control of the city of Thebes and ended up killing each other. They introduce Creon as the new king.
The second role of the Chorus is to stand in for the audience, providing the response that the playwright intends the audience to have to the unfolding drama. Thus, at the beginning of the play, the elders are firmly on the side of Creon, expounding on the right of kings to make and enforce law. But as Antigone and Haemon make their arguments, the Chorus begins to waver. When Tiresias arrives and reveals the anger of the gods toward Creon's decree that Polynices should not be buried, the Chorus swings fully over to Antigone's side. At the end of the play, the Chorus wails, "Ah me, how all too late thou seemest to see the right!" This voices the feelings of the audience at the tragedies that have befallen Creon because of his pride.
Finally, the Chorus allows the playwright to show off the beauty of his language in lyrical odes. The Chorus recites several impressive odes, including the "Ode to Man" and the "Ode to Zeus," which display Sophocles's prowess as a poet. This elevated diction rewards the audience with a sophisticated level of entertainment that they can find nowhere else.
In Antigone, Sophocles makes effective use of the Chorus as a narrator, a stand-in for the audience, and a showcase for his poetic language.