history
From 《论语·子路》: 君子和而不同，小人同而不和 - Confucius contrasts the gentleman, who seeks harmony without losing individuality, with the petty man, who forces outward agreement while harboring discord.
usage
Often cited in diplomacy, corporate culture, and discussions of pluralism. The point is not suppressing difference but coexisting with it - contrast with 随声附和 (blindly agreeing).
