起信論疏筆削記 3.7

3.7

依心開門者，以論云：依一心法有二種門也。真如門者，於中有離言依言，依言之中復有空不空二，具如下說。頓教分者，以此門中說心性不生不滅，乃至離言絕慮等義，故當此教。密說者，如《心經》云：是諸法空相，不生不滅，不垢不淨，不增不減等，即是真如之相。雖明其相，而不克顯真如體性，故云密說，理實無異，故今配之。

"Opening the gates relying on the mind": because the treatise says, "Relying on the dharma of the One Mind, there are two gates." "Gate of tathatā": within it, there are [the aspects] beyond words and according with words; within that according with words, there are again empty and non-empty, as fully explained below. "Part of the sudden teaching": because this gate explains that the nature of mind is neither arising nor ceasing, up to being beyond words and cut off from thoughts, it corresponds to this teaching. "Esoterically explained": as the Heart Sūtra says, "These dharmas' mark of emptiness: neither arising nor ceasing, neither defiled nor pure, neither increasing nor decreasing," etc., which are the marks of tathatā. Although it clarifies its marks, it does not specifically reveal the essential nature of tathatā, hence it says "esoterically explained." In principle there is truly no difference, hence it is correlated now.