《后汉书·列传·西羌传》
从前，先王治理九州，分别王畿和边远地区，知道夷貊性情不同，难以用道德驾驭，所以将他们远远地排斥在华夏之外，减少他们的贡赋，仅仅同他们约盟而已。
昔先王疆理九土，判别畿荒，知夷貊殊性，难以道御，故斥远诉华，薄其贡职，唯与辞要而已。
In the past, the first king ruled the nine provinces, distinguishing between the royal domain and the frontier regions. He knew that the Yi and Mo had different temperaments and were difficult to control with morality. Therefore, he kept them far away from Huaxia, reduced their tributes, and only made alliances with them.