The Chorus, Orestes, and Electra switch off saying prayers. The Chorus begins by calling for the powers of destiny to press on now. Revenge must be paid and "the one who acts must suffer." Orestes speaks next, making a prayer to Agamemnon. He asks what words can reach him now, what light can oppose his darkness. The chorus replies, saying that the rage of the dead inflames the sons still living. Electra joins in, saying that she and Orestes are one in their misery. No one can escape doom.
The chorus says that there is hope for this mournful song to turn to joy, and for them to sing a song of triumph. Orestes and Electra then dwell on what could have happened to prevent their present misery. If only, Orestes says, Agamemnon had died a glorious death at Troy. Then he and Electra could have basked in his glory and been the envy of all. The leader of the chorus picks up on this idea, saying that Agamemnon could have ruled among the kings of the dead. Electra wishes instead that the murderers had been slain first so that Agamemnon would never had been killed.
The chorus puts an end to this musing, saying "[d]reams are easy, oh, but the double lash is striking home." The time for the children to take victory is now. Inspired by this, Orestes calls for Zeus to force up destruction from the earth. The chorus grows more excited, foreseeing its triumphant cries when "the man is stabbed, the woman dies." Their hatred is rising to a furious pitch. Electra joins in now, crying, "Zeus, crush their skulls! Kill! Kill!"
The chorus justifies these murderous cries by saying that "it is the law." Blood must be paid for with blood. Orestes nearly loses himself in his misery, and the chorus sinks low with him, but then rebounds. Emotions are running high at this point, and hope and despair swing back and forth across the stage.
But, just as they say that they have found new hope in Orestes, Electra cries out, "What hope?" Their miseries are past soothing, she says, even by a mother's touch. Clytamnestra will never be able to calm the "wolves' raw fury" that she has bred. She dared to bury their father unwept and unsung, so now she must pay. The chorus focuses in on Clytamnestra as well, providing excruciating details of her crimes. "Butchered, I tell you—hands lopped, strung to shackle his neck and arms!" They work to cultivate this vehement hatred brewing in Orestes and Electra's hearts.
Electra reminds them that she, too, deserves pity. Clytamnestra leashed her like a dog in a cell, leaving her to weep in vain.
The chorus tells Orestes and Electra to burn with fury, but to make their hearts stand firm. This anger must be turned to a purpose: revenge. Hearing this, Orestes and Electra call out to their father to help them battle their enemies. The chorus shudders to hear these prayers, but rejoices that the hour of light has come to dispel the gloom. As they exit the stage, they sing one last prayer to the gods to come to the children's aid.
This section of the tragedy is called the kommos, which is the Greek name for an ecstatic dirge in the form of a lyric dialogue between the chorus and one or more of the actors. The purpose of this kommos is to invoke Agamemnon's aid against Clytamnestra and Aigisthos. There was a precedent in the Greek theater for the ghost of a dead man to actually appear following such an invocation, leaving the audience in suspense in this situation as to whether Agamemnon is about to appear. While he does not make an entrance onto the stage, from this point on his presence is felt as Orestes drives towards his murderous goal. There is a tension here between two different images of the afterlife, for the Greeks thought of a spirit as both lying with its body, and also being in Hades.
Up until this point in the play, Orestes has stated that he is acting solely on Apollo's command in returning home to avenge his father. However, in this scene, both he and Electra rise into a frenzy of anger, and from now until the fatal moment Orestes takes personal responsibility for the deed. Apollo will not return as a driving force until the very moment of murder, when Orestes hesitates to kill his mother. Until that point, we see that Orestes is single- mindedly driven by his anger to exact revenge.
The chorus opens the kommos by stating the basic premise of the Oresteia, that "The one who acts must suffer." For every action, there is a reaction that must follow according to the ancient laws. The chorus appeals to the moirai, powerful goddesses of fate. They are associated with the Furies in that they ensure the connection between cause and effect, between debt and payment, and guilt and atonement. They have been at work in the house for three generations. The bloodletting of the house began when Agamemnon's father Atreus punished his brother Thyestes for sleeping with his wife. He pretended a reconciliation, but then served his brother's sons to him as a feast. This is the premise behind Aigisthos's anger against Agamemnon, and sets in motion the train of bloody events that leads to this play.
Thus, the law that the doer of a crime must suffer has been the law of the house for three generations. First, Atreus was justified in killing Thyestes for his crime, but his son, Agamemnon, dies at the hands of Aigisthos, in partnership with Clytamnestra. Clytamnestra was also justified in killing Agamemnon after he killed her daughter, but this does not exempt her from punishment. In the same way, Orestes must kill his mother, but there is no guarantee that the gods will protect him afterwards. In fact, it is to be expected that some other force will appear to exact vengeance upon him for his deeds. Nevertheless, he must go forth with his plan.
The chorus takes it upon itself in this scene to guide and goad the royal children towards their deadly plan, which is the murder of their mother. When Orestes and Electra indulge in wishful thinking as to what might have been, the chorus snaps them back into the present, saying, "Dreams are easy, oh, but the double lash is striking home." They then force the children to acknowledge the true meaning of the words "the doer must suffer." Until now, they have avoided any direct discussion of matricide, speaking only in the abstract about vengeance for their fathers' death. The chorus brutally reminds the children of what their father has suffered, saying that he was "butchered, I tell you—hands lopped, strung to shackle his neck and arms! So she worked, she buried him, made your life a hell. Your father mutilated—do you hear?" (lines 439–443). With these gruesome words, the chorus implants an image in Orestes and Electra's minds that will not fade easily. Far from standing idly by as they do in many other tragedies, the chorus of the Libation Bearers incites the main characters to action.