Since Sophocles followed closely the tragic structure that required the tragic Hero to have a tragic flaw, it is important, when considering examples to answer your question, to identify that Oedipus' tragic flaw was his rash and prideful quick temper.
Beginning on line 673, Creon says to Oedipus:
I see you sulk in yielding and you're dangerous
when you are out of temper; natures like yours
are justly heaviest for themselves to bear.
And earlier, Teiresias the seer, says (from line 338):
You blame me my temper but you do not see
your own that lives within you
The reason that it is important the these characters observe that Oedipus is sort-tempered and rash, is that this is the quality that prompted him to murder his father, Laius, when he met him at a crossroads and neither would give way to let the other pass.
It was that murder that led him to Thebes and Jocasta (his mother) and the kingship that would be his undoing.
At the opening of Oedipus Rex, audiences learn that the people of Thebes seek Oedipus's help in understaning why the city has recently been plagued by death and destruction. (We later learn that the gods are punishing the city because Laius's killer has gone unpunished.)
In line 44, the Priest, pleading to Oedipus to help save the people of Thebes, calls Oedipus "greatest in the eyes of all," and notes that Oedipus was the only person who was able to solve the Sphix's riddle and free Thebes from its last plague.
Though Oedipus, a character who fits the description of Aristotle's tragic hero, ultimately experiences a reversal of fortune during the course of the play, the Chorus reminds audiences that Oedipus was a good leader:
People of our country Thebes, behold this Oedipus,
who knew the famous riddle and was a most powerful man,
whose fortunes all the citizens watched with emulation, how deep the sea of dire misfortune that has taken him! (1553-1556)