法華玄論 9.122

9.122

答：唯有二緣，一菩薩則報身化之、二聲聞則應身化之。法身唯佛能見，故不說法也。又法身名相斯絕，豈有音聲說法？說法之事皆是應身。

Answer: There are only two kinds of capacities: first, bodhisattvas, whom the reward body converts; second, śrāvakas, whom the response body converts. The dharmakāya can be seen only by a Buddha; therefore it does not expound the Dharma. Furthermore, names and marks are utterly severed in the dharmakāya; how could there be sounds expounding the Dharma? The act of expounding the Dharma belongs entirely to the response body.