Answer and Explanation:
Jocasta explains that she does not trust the words of the prophets, because in the past, a prophet told her ex-husband that his son would kill him. In fear, her ex-husband drove the child out of the city and was killed years later, at a crossroads by a band of thieves, just before Oedipus arrived. This makes Oedipus very afraid, as it confirms the prophecy he received.
That's because Oedipus knows that he is not a legitimate child of the parents who raised him and that he was found as a baby. In addition, he killed a man near the crossroads to which Jocasta's ex-husband was killed. In that case, it is likely that he killed her husband and then married her, which proves the terrible prophecy he received that said he would kill his own father and lie with his own mother.