The Doctrine of the Mean. Chapter 7.
The Master said, "Men all say, 'We are wise'; but being driven forward and taken in a net, a trap, or a pitfall, they know not how to escape. Men all say, 'We are wise'; but happening to choose the course of the Mean, they are not able to keep it for a round mouth."
Text source: The Doctrine of the Mean. Translated by James Legge.