大乘起信論廣釋卷第三．四．五 5.33

5.33

論。證何境界至名為法身　釋曰。此證何境。境界所謂真如者。初舉所證法。以依轉識說為等者。次釋通外難。既體名證。則無能所。何故說真名之為境耶。答此難言以依等。有義轉識即阿黎耶。十地證智要依此起。以此黎耶能取境界故。就所依說真為境。實能證智與所證理平等平等無境界也。有義。不然不異前說。而有能證所證別故。應知此中言轉識者。假指證智同時轉相。謂諸菩薩雖體真如。猶有業相微細生滅。有業相故未離轉現。欲顯菩薩非淳淨證。假就此識說真為境　而實證者體會真如理智無別。何有境界。唯真如智名法身者。後結明非境。謂證菩提名為法身。法身唯是真如淨智。非謂理智而有差別。是故真如非境界也。

[Treatise:] What realm is realised? […] is termed the dharmakāya.
[Commentary:] "What realm is realised? The realm is so-called suchness": first, the text adduces the Dharma that is realised. "Because it is based on the evolving consciousness, it is spoken of as […]": next, this resolves an external objection. If realization is by nature experiential realization, then there is no subject or object; why then speak of suchness as a "realm"? In reply to this objection, it says "Because it is based on […]".
One view holds: The evolving consciousness is the ālayavijñāna. The cognitive realization of the ten grounds must arise based on this. Because this ālayavijñāna is able to grasp realms, suchness is spoken of as a realm with respect to its basis. In reality, the cognitively realising cognition and the realised principle are utterly equal, without any realm.
Another view holds: Not so. This does not differ from the previous view, yet retains the distinction between realised and realiser. One should know that the "evolving consciousness" spoken of here is a metaphorical reference to the evolving mark simultaneous with the cognition of realization. That is, although the bodhisattvas experientially realise suchness, they still possess the subtle arising and ceasing of the mark of karma. Because they have the mark of karma, they are not yet free from manifestation and appearance. Wishing to show that the bodhisattvas' realization is not yet purely clean, it metaphorically speaks of suchness as a realm on the basis of this consciousness. Yet in true realization, experiential realization of suchness has no distinction between principle and cognition—how could there be a realm?
"Only suchness cognition is called the dharmakāya": finally, this concludes by clarifying that it is not a realm. That is, realizing bodhi is termed the dharmakāya; the dharmakāya is merely the pure cognition of suchness, and does not mean that there is any difference between principle and cognition. Therefore, suchness is not a realm.