仁王經疏 2.421

2.421

釋曰：第三、智理相對讚入真義。此無二者，一牒上於解常一義。謂無分別智證一如來外無別俗諦，故言通達此無二，真入第一義。

Explanation: Third, contrasting wisdom and principle, it praises entry into the meaning of the ultimate. "This non-duality" reiterates the preceding meaning of "in understanding, they are always one." That is, because non-conceptual wisdom realizes the one tathatā outside of which there is no separate conventional truth, it therefore says: "Comprehending this non-duality, one truly enters the paramārtha-satya."