大乘起信論裂網疏 4.68

4.68

此示大乘自體相也。一切眾生心既本具真如體，即本具真如相，非俟成佛而後有之，故名真如自體相也。非同非異者，約翻染差別故非同，約唯一真如故非異也。依真如體本具如此真實德相，故約凡夫日用不知，但名為如來藏；約諸佛出障圓明，轉名為法身也。初正顯示竟。

This reveals the own-essence and attributes of the Mahāyāna. Since the minds of all sentient beings originally possess the essence of tathatā, they also originally possess the attributes of tathatā; these do not wait until one attains Buddhahood to exist, so they are called the own-essence and attributes of tathatā. "Neither identical nor different": in terms of overturning defilement with differentiations, they are not identical; in terms of being solely the one tathatā, they are not different. Because the essence of tathatā originally possesses such real virtuous attributes, in terms of ordinary people who use it daily without knowing, it is merely called the tathāgatagarbha; in terms of the Buddhas who have emerged from obstacles and are fully illuminated, it is re-named the dharmakāya. The first part, correctly revealing, is finished.