《资治通鉴·唐纪·唐纪十一》
太宗对身边大臣说： 中原王朝是树木的根基，四方民族乃是其枝叶；割断树根以奉养枝叶，树怎么能生长繁茂呢？
上谓侍臣曰： 中国，根幹也；四夷，枝叶也；割根幹以奉枝叶，木安得滋荣！
Taizong told the ministers beside him: the Central Plains dynasty is the base of the tree, and other nations are the branches and leaves; if we cut the base to feed the branches and leaves, how can the tree grow well?