瑜伽論記 12.505

12.505

謂有、非有、不可說者，真如無相離言性不可說有及以非有。言即色、雜色，不可說故者，色礙如不礙不可說即，即色辨如故不說離，乃至即識離識不可說義，例前應知。

Regarding 'ineffable as existent or non-existent': tathatā is markless and its nature is free from language, so it cannot be spoken of as existent or as non-existent. Regarding the statement 'because it cannot be spoken of as identical with form or separate from form': form is obstructive while tathatā is unobstructive, so it cannot be spoken of as identical; yet because tathatā is discerned based on form, it is not spoken of as separate; extending to the point that the meaning of being ineffable as identical with consciousness or separate from consciousness should be understood by analogy with the above.