Mencius - Book 2, Part 2, Chapter 5

Mencius said to Ch'î Wâ, 'There seemed to be reason in your declining the governorship of Ling-ch'iû, and requesting to be appointed chief criminal judge, because the latter office would afford you the opportunity of speaking your views. Now several months have elapsed, and have you yet found nothing of which you might speak?'

On this, Ch'î Wâ remonstrated on some matter with the king, and, his counsel not being taken, resigned his office and went away.

The people of Ch'î said, 'In the course which he marked out for Ch'î Wâ he did well, but we do not know as to the course which he pursues for himself.'

His disciple Kung-tû told him these remarks.

Mencius said, 'I have heard that he who is in charge of an office, when he is prevented from fulfilling its duties, ought to take his departure, and that he on whom is the responsibility of giving his opinion, when he finds his words unattended to, ought to do the same. But I am in charge of no office; on me devolves no duty of speaking out my opinion: may not I therefore act freely and without any constraint, either in going forward or in retiring?'
~ James Legge translation via nothingistic.org ~

Go here to read the introductory post to this serialized version of the Works of Mencius.