俱舍論疏 6.128

6.128

論「若爾所緣至為相應因」，此釋頌中相應，有同一所緣、同一行相、同時、同依。然頌唯說同依意者，由一所依義最要故，所以偏說。

The treatise says, "If so, object-support [...] as associated causes," which explains that association in the verse entails having the same object-support, the same mental aspect (ākāra), the same time, and the same basis (āśraya). However, the verse speaks only of having the same basis because the meaning of a single basis is the most essential, which is why it is specifically mentioned.