俱舍論記 4.107

4.107

「此中應說至決定俱生」者，此下大文第二明定俱生。就中，一約欲界俱生、二約上界俱生。此下約欲界俱生，頌前問起。

Regarding "Here it should be explained [...] definitely arise together," this begins the second major section, explaining invariable co-arising. Within this, first, co-arising with respect to the desire realm; second, co-arising with respect to the higher realms. From here down is co-arising with respect to the desire realm, asking the question before the verses.