瑜伽論記 2.406

2.406

即彼外道復作是說等者，彼計草木皆悉有命殺成業道，佛為除此說如是言真實眾生所，殺草木非業道。

"Those same non-Buddhists further state as follows," and so forth: they hold that grass and trees all have life and that killing them constitutes a course of karma. To eliminate this, the Buddha spoke thus: "in relation to real sentient beings"; killing grass and trees is not a course of karma.