瑜伽師地論略纂 5.96

5.96

於三有情中，別起為初三、總緣為後一。於無苦無樂，與樂作意者，慈、悲、喜三，如次配也。

Among the three [classes of] sentient beings, arising distinctly applies to the first three, while taking them collectively as an object applies to the last one. Toward those who have neither suffering nor pleasure, engaging in the manaskāra of granting pleasure: benevolence, compassion, and sympathetic joy correspond in respective order.