菩薩戒義疏 2.18

2.18

第三、食肉戒，斷大慈心。大士懷慈為本，一切悉斷。聲聞漸教，初開三種淨肉等，後亦皆斷。文云當知斷現肉義。《大經．四相品》廣明三種、九種、十種也。序事三階：一、明過失，二、制不應，三、舉非結過。若有重病，飲藥能治，準律得噉，或應不制。

Third, the precept against eating meat: it severs the mind of great compassion. For a mahāsattva, cherishing compassion is primary, so all [meat] is completely cut off. In the gradual teachings of the śrāvakas, the three kinds of pure meat and so forth were initially permitted, but later these too were entirely severed. The text says: "You should know that the present meaning is to sever meat." The "Four Marks Chapter" of the Mahāparinirvāṇa-sūtra explains the three kinds, nine kinds, and ten kinds in detail. The narration of matters has three stages: first, explaining the faults; second, prescribing what is not proper; third, adducing the wrongdoing and concluding the offense. If there is a severe illness and taking it as medicine can cure it, according to the Vinaya it may be eaten, or perhaps it should not be prohibited.