From 《
论语·
卫灵公》 (Analects, Wei Ling Gong chapter, ~5th-4th c. BCE):
君子义以为质,
礼以行之,
孙以出之,
信以成之。
君子哉 (The gentleman takes righteousness as substance, acts on it through ritual, expresses it with modesty, completes it with trustworthiness — such is the gentleman). A core Confucian definition of
君子 in four clauses.