成唯識論演祕 4.503

4.503

意明平等通諸地有法。觀第六引彼平等智以為所依，生空第六即以隨身界繫第七而為所依，故云不定。

The intention is to clarify the phenomenon that equality is common to all planes. The sixth [consciousness] of contemplation induces that wisdom of equality and takes it as its support; the sixth consciousness [realizing] the emptiness of persons takes the seventh consciousness bound to the realm of the body as its support; hence it is said to be unfixed.