瑜伽論記 1.78

1.78

三摩地俱者，釋雖解之，然猶未盡，意顯等引地等體通五蘊。單言三摩地不言俱者，唯一定數，不能顯得體通五蘊，故說俱言顯與等引地寬狹同故，但以橫通五蘊體同，不以竪通三界義同。

Regarding "associated with samādhi" (samādhisaṃprayukta), although the Commentary explains it, it has not yet exhausted [its meaning]. The intent is to show that the essential nature of the stage of samāhita (meditative equipoise) and the like extends across all five aggregates. If one merely said "samādhi" without saying "associated with", it would refer solely to a single mental factor of concentration (ekāgratā) and would not be able to show that its essential nature extends across the five aggregates. Therefore, the word "associated with" is stated to show that its breadth is identical with the stage of meditative equipoise; this is because they share the same essential nature in horizontally extending across the five aggregates, not because they are identical in vertically extending through the three realms.