成唯識論述記 9.459

9.459

述曰：並名為福，皆名為智，與智俱行助成智業，皆名為智；與福俱行，助成福業，並名為福。此依助伴通相出體。

The Commentary states: All are called merit and all are called knowledge: proceeding together with knowledge to assist in accomplishing knowledge-activities, all are called knowledge; proceeding together with merit to assist in accomplishing merit-activities, all are called merit. This isolates the essential nature according to their common characteristics as mutual companions.