妙法蓮華經玄義 7.47

7.47

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."