廣弘明集 27.68

27.68

今以經書交映。內外之教其本均同。正是意殊名異。若使理乖義越者。則不容有此同致。所以稱內外者本非形分。但以心表為言也。

Now, setting the sūtras and the [Confucian] books against each other, the internal and external teachings are essentially the same at the root; it is merely that their intention is distinctive and their terminology different. If their principles were contrary and their purports disparate, they could not possibly have this identical result. The reason they are called 'internal' and 'external' is fundamentally not a bodily distinction; they are spoken of only by way of the mind and the exterior.