金光明經文句記 1.157

1.157

初、他解屬體。鑛石者，《說文》云「鑛，銅鐵璞也。」內外用者，光為內用，自顯體故。明為外用，鑑他物故。此師亦知光明二字屬於宗用，金是正體，以其體用不相離故。雖標三字，意在於體也。

First, the other interpretation belonging to substance. As for "unrefined ore," the Shuowen says: "Ore is unworked copper or iron." As for internal and external functions: radiance (guang) is the internal function, because it reveals its own substance; brightness (ming) is the external function, because it illuminates other objects. This master also understood that the two characters guang and ming belong to gist and function, and "gold" is the primary substance, because its substance and functions are not separated from one another. Although he indicated the three characters, his intention resided in the substance.