Show how the good as well as bad qualities of Oedipus contribute to his tragic fall in Sophocles' Oedipus Rex
Oedipus's good qualities include his desire for justice and his will to save the people of Thebes from the plague that is devastating them. He is a strong and responsible leader who wants to decisively solve a problem that is harming his city-state.
On the bad side, Oedipus suffers from hubris (pride) which makes him blind to his own flaws. As he is promising dire punishment to whoever is responsible for bringing the plague, it never once occurs to him that the person might be him. He is blind to himself and thinks he can do no wrong.
We can easily see how Oedipus's attributes and flaws work together to create the perfect storm of tragic problems for him. Because he is so responsible about getting to the bottom of what is causing the plague, and because he won't, as advised, turn away from the investigation, he makes discoveries that upend his life. He has to accept that he is not the person he thought he was. He has to face that his self image was based on an illusion that he could defy his fate. When he fully faces the horror of having killed his father and married his mother (information which causes her to commit suicide) he blinds himself in anguish and then accepts exile from his home.
Oedipus is very forthcoming and honest. He does not feel the need to hide behind the walls of his palace, but, rather, conducts all of his business out in the open and in public (even when cooler minds, like Creon's, try to prevail). As a result, when he learns the reason for the failing crops and health of his people, he immediately tells the Theban people,
. . . if any knows the man by whom
Laius, son of Labdacus, was slain,
I summon him to make clean shrift to me.
And if he shrinks, let him reflect that thus
Confessing he shall 'scape the capital charge;
For the worst penalty that shall befall him
Is banishment—unscathed he shall depart.
He publicly declares that the killer of Laius will not be executed but will be banished from Thebes, as long as he comes forward (which, of course, Oedipus does because he does everything in public and could not hide the truth, in the end, if he wanted to). As a result, he is doomed to wander back to mount Cithaeron, the "tomb predestined for [him] by [his] sire," rather than die a quick death. He cannot hide the truth, and so his honesty becomes a lack of discretion, a tactlessness that leads to his wife's death and his own exile.
In a sense, the tragic fall or Oedipus in Sophocles' Oedipus Rex is not due primarily to his character but to a curse caused by the ways in which his ancestors had offended the gods. Although he cannot escape the curse, certain good and bad aspects of his character do affect the way in which the curse works out. An outstandingly good quality of Oedipus is his sense of responsibility which impels him to find the source of the plague in order to save Thebes. On the other hand, his determination to find the plague, which is a good characteristic in moderation, is present in excess and becomes stubbornness, leading him to ignore the wise advice of Tiresias and seek answers despite the prophet's original advice:
TEIRESIAS: I will cause neither me nor you distress.
Why do you vainly question me like this?
You will not learn a thing from me.