大乘起信論裂網疏 6.56

6.56

[Text:] Furthermore, relying on this samādhi, one realizes the marks of the dharmadhātu, knowing that the dharmakāya of all Tathāgatas and the bodies of all sentient beings are equal and non-dual, all being of one mark; therefore it is named the single-mark samādhi. If one cultivates this samādhi, one can produce immeasurable samādhis, because tathatā is the fundamental ground of all samādhis.