Confucius. Book 4, Chapter 18.
Book 4, Le Jin.
The Master said, "In serving his parents, a son may remonstrate with them, but gently; when he sees that they do not incline to follow his advice, he shows an increased degree of reverence, but does not abandon his purpose; and should they punish him, he does not allow himself to murmur."
Text source: Lun Yu, The Confucian Analects. Translated by James Legge.