Jocasta, Oedipus's wife, tells him about the murder of Lauis. She explains that the oracle had said he was going to be murdered by his son, but that in fact, he was murdered by thieves. She offers this as evidence of the falsehood of prophets. However, Oedipus wants to know more, and as he investigates, he begins to realize he might have been the one who killed Laius.
Oedipus is upset at this discovery. However, he decides that if this is true, he should face the same consequences any other person would, and he wants to find out the truth. This shows that Oedipus believes in justice, and is willing to face the consequences of his acts.