The greatest enemy to human souls is the self-righteous spirit which makes men look to themselves for salvation.
~ Charles Spurgeon
But it is the same with man as with the tree. The more he seeks to rise into the height and light, the more vigorously do his roots struggle earthword, downword, into the dark, the deep - into evil.
~ Friedrich Nietzsche, Thus Spoke Zarathustra
The deceitfulness of the heart of man appears in no one thing so much as this of spiritual pride and self-righteousness. The subtlety of Satan appears in its height, in his managing persons with respect to this sin. And perhaps one reason may be that here he has most experience; he knows the way of its coming in; he is acquainted with the secret springs of it: it was his own sin. Experience gives vast advantage in leading souls, either in good or evil.
~ Jonathan Edwards, The Religious Affections
Self-righteousness in retrospect is easy--also cheap.
~ Arthur M. Schlesinger Jr.
It takes one to know one. So I most probably am one myself.