Rooted in Confucian ethics. 《
论语·
卫灵公》 has
己所不欲,
勿施于人 (Do not impose on others what you yourself do not want), and 《
礼记》 warns
君子不强人以其所不能 (A gentleman does not press others beyond their ability). The four-character form
不强人所难 crystallized in later usage as a standard polite formula.