宋高僧傳 25.9

25.9

系曰：康所述偈讚，皆附會鄭、衛之聲，變體而作，非哀非樂，不怨不怒，得處中曲韻。譬猶善醫以餳蜜塗逆口之藥，誘嬰兒之入口耳。苟非大權入假，何能運此方便，度無極者乎？唱佛佛形從口而出，善導同此作佛事，故非小緣哉！

The appraisal says: The verses and praises composed by Kang were all set to the popular melodies of Zheng and Wei, created as transformed styles: neither mournful nor festive, neither resentful nor angry, achieving balanced melodies and rhythms. This is like a skilled physician coating an unpalatable medicine with malt-sugar and honey to entice an infant to take it into its mouth. If he were not a great manifestation entering the provisional, how could he have exercised such skillful means to deliver beings without limit? When chanting the Buddha's name, the forms of Buddhas issued from his mouth; Shan Dao engaged in Buddha-work in this same manner, so this was truly no small affinity!