Where does Aizen make this quote about self-rightfulness?
It's in episode 62.

Ukitake asks &quot;Have you become that corrupt? Have you?&quot;
Aizen replies: &quot;You're blinded by your self-righteousness. From the beginning,
no one has ever stood at the top. Neither you, nor me, nor the gods.
But soon, that unobtainable vacancy at the top will be filled.&quot;

Here is the link to the moment you are referring to.