《黄帝内经·素问·离合真邪论》
假如不懂得三部九侯，则阴阳不能辨别，上下也不能分清，更不知道从上部脉以诊察下，从上部脉以诊察上，从中部脉以诊察中，结合胃气多少有无来决定疾病在那一部。
不知三部者，阴阳不别，天地不分。地以候地，天以候天，人以候人，调之中府，以定三部。
If you are ignorant of the three parts of the body and the nine pulses, then you will not be able to tell yin and yang apart, or to tell upper from lower, and you will not even know how to use the pulse of the upper part to diagnose the lower part, or the pulse of the upper part to diagnose the upper part, or the pulse of the middle part to diagnose the middle part, or to decide in which part the disease lies based on the amount of stomach qi or its presence or absence.