You will find so many great and memorable quotes from Sophocles' work. The choices will be difficult to narrow down. One particular quote I like is from Oedipus himself:
So tell me, when are you the wise seer? (410)
How is it that, when the singing hound was here,
you never said how the citizens might be freed?
Even though the riddle could not be solved by
the first man who met it, but required prophecy.
But you did not come forth with this, knowing some clue (415)
from birds or gods; instead I came along,
If we are examining the hubris contained in Oedipus, we find it here. Though a bit length, I think that the quote is important and memorable because it fully speaks to the sense of pride and sense of ego that Oedipus possesses. While he is a great ruler and contains much in way of attributes, Oedipus sense of self, the love of oneself and the belief that one is better than one might actually be, comes out in this quote.
It seems that Sophocles would not let an opportunity like this one pass in terms of offering up something in the play that would foreshadow Oedipus' own fall. In this, Tiresias offers another quote that is memorable and in its brevity says much:
Alas, how terrible is wisdom when it brings no profit to the man that's wise!
Tiresias' quote is a wonderful moment of foreshadowing in that it reflects how there are limits to human capacity, a concept that Oedipus himself refutes throughout the drama until an ending in which he recognizes the truth of the quote too late.
I think that Oedipus' final speech at the end of the drama when he offers a prayer for his daughter to avert the condition that he endured is one of the most poignant and memorable quotes in the drama:
Suffer them not to wander husbandless/ Nor let thy kindred beg their daily bread.
In this quote, Oedipus, blind and shamed, offers the only hope possible in terms of seeing his children endure better than he did. I tend to think that this becomes one of the lasting legacies of Oedipus and something that lingers in my mind, memorable in its pain and sense of compassion. In these quotes, the spirit of the drama is evident in terms of the collision between freedom and fate, humanity and the powers larger than them.