起信論註 1.25

1.25

論一切眾生本覺真如共諸佛體性一種　難曰。一種未起智照則言覺義則屬性德。覺者對染翻得名。下文則言本覺者。因此性德能成果位則。是名本却歸本源。當顯始覺法身。是故德本覺名故（此明本覺。以了）此則明始覺也。

Treatise: The original enlightenment of tathatā in all sentient beings is of one identical essence with all Buddhas. Objection: If it is of one identical essence before the illumination of wisdom has arisen, then speaking of the meaning of enlightenment belongs to nature-virtues. "Enlightenment" receives its name by overturning defilement. The text below says that "original enlightenment" is because this nature-virtue can bring about the fruitional stage; it is called original, returning back to the original source, to reveal the dharmakāya of initial enlightenment. Therefore it receives the name "original enlightenment" (this clarifies original enlightenment, completed). This then clarifies initial enlightenment.