注維摩詰經 9.64

9.64

什曰：佛事有三種，一以善作佛事，光明神力說法等是也；二無記，虛空是也。三以不善，八萬四千煩惱是也。譬如藥師，或以良藥或以毒藥治人病也。佛亦如是以煩惱，如佛以愛度難陀也，瞋恚化惡龍比也。肇曰：眾生皆以煩惱為病，而諸佛即以之為藥。如婬女以欲為患，更極其情欲然後悟道。毒龍以瞋為患，更增其忿恚然後受化。此以欲除欲、以瞋除瞋，猶良醫以毒除毒，斯佛事之無方也。生曰：若投藥失所，則藥反為毒矣。苟曰得愈，毒為藥也。是以大聖為心病之醫王，觸事皆是法之良藥。

[Kumāra]jīva says: The work of a buddha is of three kinds: first, performing the work of a buddha through the wholesome—radiance, supernatural power, preaching the Dharma, and the like are this; second, the indeterminate—empty space is this; third, through the unwholesome—the eighty-four thousand afflictions are this. It is like a physician who cures a person's illness either with good medicine or with poisonous medicine. The Buddha is also like this with afflictions, just as the Buddha delivered Nanda through desire, or converted an evil dragon through anger. [Seng]zhao says: Sentient beings all take afflictions as illness, and the buddhas precisely use them as medicine. Just as a courtesan, suffering from desire, was made to take her lust to the extreme and only then awakened to the Path; or a venomous dragon, suffering from anger, had its fury further increased and only then received conversion. This is eliminating desire by means of desire, and eliminating anger by means of anger, just as a good physician eliminates poison by means of poison; such is the boundless modality of the work of a buddha. [Dao]sheng says: If the administration of medicine misses its mark, then medicine conversely becomes poison. Provided that healing is achieved, poison is medicine. Therefore the Great Sage is the king of physicians for mental illnesses; every affair he touches upon is a good medicine of the Dharma.