大乘起信論別記 1.181

1.181

言「自體相」者，總舉二種，本言一切眾生乃至諸佛無有增減畢竟常住，是釋體大。上立中云「一者體大，謂一切法真如平等，不增減故。」

The phrase "self-essence and characteristic" brings up both together. The original text stating that from all sentient beings up to the Buddhas there is neither increase nor decrease and it is ultimately eternal, explains the greatness of essence. In the establishment above it says: "First is the greatness of essence, meaning that the tathatā of all dharmas is equal, neither increasing nor decreasing."