法華玄論 7.60

7.60

答。有同有異。異者，雲雨來意，如說經因緣中辨之。今略舉二意：一者取無心而能普益、二者欲顯同一正道隨根成異也。一音者，欲明如來三密不可思議，凡夫二乘不能測度。所以然者，下位之人但以一音令緣同聞一，不能以一音令萬類異聞，唯佛能爾，故名口密不可思議也。

Answer: There are both sameness and difference. As for the difference: the intent behind the cloud and rain is as distinguished in the causes and conditions for expounding the sūtra. Here we briefly raise two points: first, it takes being without mind yet able to benefit universally; second, it wishes to reveal the identical correct path becoming different according to faculties. As for the single voice: it wishes to clarify that the Tathāgata's three mysteries are inconceivable, and cannot be fathomed by ordinary beings or the two vehicles. Why is this? A person of a lower stage can only use a single sound to cause [those with] conditions to hear the same one thing together; they cannot use a single voice to cause myriad kinds to hear differently. Only the Buddha is able to do so, and hence it is called the inconceivable mystery of speech.