摩訶止觀 7.41

7.41

若觀法性受，法性因緣生故，一種一切種，一受一切受。法性受空故，一切受一受，一空一切空。法性受假名故，一受一切受，一假一切假。法性受中故，非一受非一切受，非空非假雙照空假，則一切非空非假雙照空假。九法界受即空、即假、即中，亦復如是。是名「受念處」。

If one contemplates feelings in the dharmatā, because the dharmatā arises from causes and conditions, one kind is all kinds, and one feeling is all feelings. Because feelings in the dharmatā are empty, all feelings are one feeling, and one emptiness is all emptiness. Because feelings in the dharmatā are provisional designations, one feeling is all feelings, and one provisionality is all provisionality. Because feelings in the dharmatā are middle, they are neither one feeling nor all feelings, neither empty nor provisional while simultaneously illuminating emptiness and the provisional, and thus all is neither empty nor provisional while simultaneously illuminating emptiness and the provisional. Feelings in the nine dharmadhātus are identical to emptiness, identical to the provisional, and identical to the middle, and are also like this. This is called the “mindfulness of feeling” (vedanāsmṛtyupasthāna).