摩訶止觀 8.192

8.192

魔界即佛界，而眾生不知，迷於佛界，橫起魔界，於菩提中而生煩惱，是故起悲。欲令眾生於魔界即佛界、於煩惱即菩提，是故起慈。慈無量佛，悲無量魔，無量慈悲即無緣一大慈悲也。

The māra-realm is itself the Buddha-realm, yet sentient beings do not know this; deluded about the Buddha-realm, they crosswise give rise to the māra-realm, and within bodhi they generate afflictions—therefore compassion arises. Wishing to cause sentient beings to find the Buddha-realm right within the māra-realm, and bodhi right within afflictions—therefore benevolence arises. Benevolence is immeasurable Buddhas; compassion is immeasurable māras; immeasurable benevolence and compassion is none other than the unconditioned great benevolence and compassion.