大乘起信論義記 3.177

3.177

In the conclusion below: it says 'not separated' because the sands of the nature's virtues are not separated from the true substance; it says 'not interrupted' because they continue from the beginningless [past], or it can also mean that the path of antidote does not perish. It says 'not different' because they have the same taste as the substance; it says 'inconceivable' because while not different, they have the meaning of the sands of the Ganges; it says 'Buddha-dharmas' because only Buddhas exhaustively penetrate them, or it can also mean that these are the dharmas that are enlightened to. If this true substance lacked the virtues of the nature, the Tathāgata, in realizing this, would not be complete with virtues; but since having realized the nature, the myriad virtues are complete, this verifies that tathatā fundamentally possesses virtues [numerous as] the sands of the Ganges; hence it says 'replete without lacking anything'. Below two names are established: when hidden, being able to give birth to the Tathāgata, it is named tathāgatagarbha; when revealed, being the support for the myriad virtues, it is named dharmakāya.