大般涅槃經集解 56.88

56.88

案僧亮曰：第六難，五味相生，因有強弱，乳強故不假外緣也。寶亮曰：舉經為證。昔說三乘僧常，若爾者，則應常住僧位，云何成佛耶？

Sengliang states: The sixth objection: the five flavours arise from one another, and causes have strengths and weaknesses; because milk is strong, it does not rely on external conditions. Baoliang states: He cites the sūtras as proof. Formerly it was said that the Saṅgha of the three vehicles is permanent; if so, they ought to abide permanently in the rank of the Saṅgha, so how could they attain buddhahood?