《逸周书·卷七·官人解》
身有方术而不丢弃，廉洁自爱而不休止，刚强自立而无私心，叫做有经者。
直方而不毁，廉洁而不戾，强立而无私，曰有经者也。
Having skills but not abandoning them, being honest and self-respecting without ceasing, being strong and independent without selfishness, is called having principles.