大般涅槃經義記 5.296

5.296

下有兩對，境、智分別。「非色說色、色說非色」，就境分別，於理非色隨俗說色，世諦之色就理言非。「非道說道、道說非道」，就智分別，類色可解。

Below there are two pairs, differentiated by object and cognition. "Preaching form regarding what is not form, and preaching non-form regarding form" is differentiation with respect to the object: in principle it is not form, yet conforming to convention form is preached; regarding form of conventional truth, in terms of principle it is said to be non-[form]. "Preaching the path regarding what is not the path, and preaching the non-path regarding the path" is differentiation with respect to cognition; it can be understood by analogy with form.