《黄帝内经·素问·阴阳别论》
歧伯回答说：四经，是指与四时相应的正常脉象，十二从，是指与十二个月相应的十二经脉。
岐伯对曰：四经应四时；十二从应十二月；十二月应十二脉。
Qibao replied: The four classics refer to the normal pulse象 corresponding to the four seasons, and the twelve followers refer to the twelve meridians corresponding to the twelve months.