By definition, as a tragic hero, Oedipus Rex is a man of noble stature who is good, albeit not perfect because he commits "an act of injustice" which leads to his downfall.
What makes Oedipus noble are his virtues:
1. Oedipus is wise. First of all, he has solved the riddle of the Sphinx; then, he knows to seek the seer Teiresias, and when he speaks with Kreon in the Prologue, he promises that again he will "bring what is dark to light" and rid the city of Thebes of evil. While at first he becomes angry with the things that Teiresias informs him of, Oedipus later tells Jocaste,
"I am not sure that the blind man can not see." (703)
2. Oedipus is compassionate. He even feels empathy for the people of Thebes when he learns of their suffering,
My poor children, what you desire is
known and not unknown to me, for I see well
that everyone is sick, and being sick,
still, not one of you is as sick as I am. (63-66)
4. Oedipus has integrity. When the memory of the place of the incident at the place where three roads meet, He tells the people of Thebes that he promises to avenge their city and be rid of the evil. Early on, Kreon has told him that at Delphi the gods declared that the "old defilement" must be either killed or exiled. After his discovery of the truth, Oedipus, true to his word, blinds himself and goes into a self-imposed exile.
5. Oedipus is solicitous of his daughters.
As Oedipus prepares to depart Thebes at the end of the play, he says to his children,
I could say much, if you could understand me,
But as it is, I have only this prayer for you:
Then may you be blessed, and for this meeting
may fate guard you better than it did me (1498-1501)