大乘起信論裂網疏 2.30

2.30

This clarifies that "genuinely non-empty" means that if one can only realize that deluded thoughts are originally empty, the true mind is revealed to be eternal and immutable, replete with pure dharmas, and so it is expressed as non-empty; it is not the same as the mark of non-emptiness conceived by deluded thoughts. If one takes the non-emptiness conceived by deluded thoughts to be the mark of tathatā, that would be identical to the conception of other schools that apart from form, mind, and so forth there is a real, permanent dharma called tathatā—which is an extreme error. In the text, "eternal" is the virtue of permanence; "immutable" is the virtue of self; "pure dharmas" is the virtue of purity; "replete essence" is the virtue of bliss. The four virtues are inconceivable; hence it is realized only by those who are free from thoughts. The first part, explaining the aspect of tathatā, is concluded.