Take no weapons. No shield. No army. Go alone—a hand in the night. Snare them. Slaughter them. You have the right.
This is the oracle of Apollo, recalled in retrospect by Orestes as he sets his plan for revenge into motion. Although the oracle is received before the events of the play begin, it plays a crucial role in terms of both plot and thematic development. While Electra is emotionally motivated to revenge by an intense desire for justice, Orestes has not shared her experiences, nor has he suffered as his sister has at the hands of his father's killers. His primary motivation, then, is the accurate fulfillment of Apollo's oracle. Throughout the play, he tailors his actions to correspond to Apollo's requirements, and he judges his success to be "good" only insofar as the oracle was "good." The wording of the oracle introduces important thematic elements as well. It introduces the motif of a "trap," which is applied primarily to the revenge itself, but more broadly and abstractly to the desire for revenge and also to the conditions of life in the home of Clytemnestra and Aegisthus, both as described by Electra. The oracle's wording is also crucial in that it includes the word "right;" that word lends sanctity to a matricidal revenge that becomes increasingly questionable as the play progresses.