There is less action in this play than in Oedipus the King, and more philosophical discussion. Here, Oedipus discusses his fate as related by the oracle, and claims that he is not fully guilty because his crimes of murder and incest were committed in ignorance. Despite being blinded and exiled and facing violence from Creon and his sons, in the end Oedipus is accepted and absolved by Zeus.
In the years between the play's composition and its first performance, Athens underwent many changes. Defeated by the Spartans, the city was placed under the rule of the Thirty Tyrants, and the citizens who opposed their rule were exiled or executed. This certainly affected the way that early audiences reacted to the play, just as the invasion of Athens and its diminished power surely affected Sophocles as he wrote it.
The play contrasts the cities of Athens and Thebes quite sharply. Thebes is often used in Athenian dramas as a city in which proper boundaries and identities are not maintained, allowing the playwright to explore themes like incest, murder, and hubris in a safe setting.
While the two other plays about Oedipus often bring up the theme of a person's moral responsibility for their destiny, and whether it is possible to rebel against destiny, Oedipus at Colonus is the only one to address it explicitly. Oedipus vehemently states that he is not responsible for the actions he was fated to commit.
‘Oedipus at Colonus’ suggests that, in breaking divine law, a ruler’s limited understanding may lead him to believe himself fully innocent; however, his lack of awareness does not change the objective fact of his guilt.
Nevertheless, determination of guilt is far more complex than this, as illustrated by the dichotomy between the blessing and the curse upon Oedipus. He has committed two crimes which render him a sort of monster and outcast among men: incest and patricide. His physical suffering, including his self-inflicted blindness, and lonely wandering, are his punishment. However, in death, he will be favored; the place in which he dies will be blessed. This suggests that willful action is in some part of guilt; the fact that Oedipus is “rationally innocent” – that he sinned unknowingly – decreases his guilt, allowing his earthly sufferings to serve as sufficient expiation for his sins.
A possible heroic interpretation of Oedipus
Darice Birge has argued that Oedipus at Colonus can be interpreted as a heroic narrative of Oedipus rather than a tragic one. It can be viewed as a transitional piece from the Oedipus of Oedipus Tyrannus whose acts were abominable to the Oedipus we see at the end of Oedipus at Colonus, who is so powerful that he is sought after by two separate major cities. The major image used to show this transition from beggar to hero is Oedipus' relationship with the sacred grove of the Erinyes. At the beginning of the play, Oedipus has to be led through the grove by Antigone and is only allowed to go through it because as a holy place it is an asylum for beggars. He recognizes the grove as the location once described to him in a prophecy as his final resting place. When Elders come looking for him, Oedipus enters the grove. This act, according to Birge, is his first act as a hero. He has given up his habit of trying to fight divine will (as was his wont in Oedipus Tyrannus) and now is no longer fighting prophecies, but is accepting this grove as the place of his death. Oedipus then hints at his supernatural power, an ability to bring success to those who accept him and suffering to those who turned him away. Oedipus' daughter Ismene then arrives, bringing news that Thebes, the city that once exiled Oedipus for his sins, wants him back for his hero status. Ismene furthers Oedipus' status as a hero when she performs a libation to the Erinyes, but his status is fully cemented when he chooses a hidden part of the sacred grove as his final resting place, which even his daughters can't know.