瑜伽論記 9.9

9.9

信言者，以音聲為體，若准此文體是異熟，所以然，此處明八種異熟既云信言具足，故知音聲。又善戒經云：言語微妙，知是異熟也。

Credible speech: this takes sound as its entity. If based on this text, its entity is vipāka. Why is this so? In clarifying the eight vipāka [entities], since it says “endowed with credible speech,” we know it is sound. Furthermore, the Bodhisattvacaryānirdeśa states: “subtle and wonderful speech,” so we know it is vipāka.