大乘法苑義林章 6.5

6.5

別體者，《涅槃經》第五，佛言：「憍曇彌！莫供養我，當供養僧。若供養僧，即得具足供養三歸。」摩訶波闍波提言：「眾僧之中無佛無法，云何說言供養眾僧即得具足供養三歸？」我復告言：「汝隨我語，即供養佛。為解脫故，即供養法。眾僧受者，即供養僧。是故三歸不得為一。善男子！如來或時說一為三、說三為一。如是之義，諸佛境界，非諸聲聞、緣覺所知。」

As for distinct essence, in Chapter Five of the Nirvāṇa-sūtra, the Buddha said: "Gautamī! Do not make offerings to me; you should make offerings to the Saṅgha. If you make offerings to the Saṅgha, you will fully complete offerings to the Three Refuges." Mahāprajāpatī said: "Among the Saṅgha there is no Buddha and no Dharma; why do you say that by making offerings to the Saṅgha one fully completes offerings to the Three Refuges?" I told her again: "If you follow my words, that is making offerings to the Buddha. For the sake of liberation, that is making offerings to the Dharma. When the Saṅgha receives them, that is making offerings to the Saṅgha. Therefore, the Three Refuges cannot be made into one. Good son! Sometimes the Tathāgata explains one as three, and sometimes three as one. Such meaning is the realm of the Buddhas, not what śrāvakas and pratyekabuddhas can know."