菩薩戒本疏 1.38

1.38

制意釋名者，命是形根有生所貴，凡在含靈莫不寶重。故《涅槃經》佛誡闍王：雖復人畜貴賤有殊，寶命重死無有異也。然則大士為懷仁慈居先，寧容恣己快心奪彼所重？特違慈行故先制之。又聲聞脫縛為先故首制婬，菩薩慈濟為上故初禁殺。又此十重七眾共持，故殺戒在初。釋名者，報形相續假名為「生」，違緣逼害名之為「殺」。

Regarding the intention behind the prohibition and explanation of the name: life is the root of the physical form and that which is treasured by the living; among all who possess sentience, there is none who does not cherish it. Therefore the Mahāparinirvāṇa-sūtra records the Buddha admonishing King Ajātaśatru: "Although humans and animals differ in status, in treasuring life and shrinking from death there is no difference." This being so, since the Great Being cherishes humaneness and compassion foremost, how could he permit himself to indulge his own heart's content and rob them of what they hold dear? Because it exceptionally contradicts the practice of compassion, it was prohibited first. Furthermore, because the śrāvaka takes escaping bondage as primary, he first prohibits sexual misconduct; because the bodhisattva takes compassionate salvation as supreme, he initially forbids killing. Furthermore, because these ten grave precepts are maintained in common by the seven assemblies, the precept against killing comes first. Regarding the explanation of the name: the continuous succession of the physical retribution body is provisionally named "life"; violating conditions that harass and harm it is named "killing."