妙法蓮華經玄義 7.47

7.47

、二理教明本迹者，即是本時所照二諦，俱不可說，故皆名本也。昔佛方便說之，即是二諦之教，教名為迹。若無二諦之本，則無二種之教，若無教迹，豈顯諦本？本迹雖殊，不思議一。文云：「是法不可示，言辭相寂滅，以方便力故，為五比丘說。」

Second, regarding principle and teaching as the original source and the traces: the two truths illuminated at the original time are both inexpressible, and thus both are named the original source. The former Buddha preached them by expedient means, which is the teaching of the two truths, and the teaching is named traces. If there were no original source of the two truths, there would be no two kinds of teaching; if there were no traces of teaching, how could the original source of the truths be revealed? Although original source and traces are distinct, they are an inconceivable unity. The text says: "This Dharma cannot be shown; the characteristics of words are extinguished. Through the power of expedient means, it was preached for the five monks."