成唯識論述記 4.325

4.325

述曰：勿有前說不具四義過，及有此識最後失故。唯異熟法是正實趣生，若有第八識，一切時恒有，無此過難由，以異熟法為正實趣生故。

The Commentary states: To avoid the aforementioned fault of failing to possess the four characteristics, and the final error of this [sixth] consciousness, only the phenomenon of retribution is the true, real destiny and realm. If there is the eighth consciousness, which is constantly present at all times, there are none of these objections and faults, because the phenomenon of retribution constitutes the true, real destiny and realm.