涅槃經遊意 1.14

1.14

何者病耶？常病重故，設無常之藥。眾生執有為涅槃故設無，身心皆盡乃為妙極，物情不了便謂佛身無涅槃斷滅。故經云：其復不久，王復得病，須服乳藥。故今教為對無常故設常住，則左右除病，迭代破執。執病若盡，在藥皆除。

What is the disease? Because the disease of permanence was severe, the medicine of impermanence was provided. Because sentient beings clung to existence as nirvāṇa, nonexistence was provided, holding that the complete exhaustion of body and mind is the ultimate subtlety; yet because beings' minds did not comprehend, they then said that the Buddha's body does not exist and nirvāṇa is total annihilation. Therefore the sūtra says: not long after, the king fell ill again and had to take the medicine of milk. Therefore the present teaching provides permanence to counter impermanence; thus on both sides diseases are removed, sequentially demolishing attachments. If the diseases of attachment are exhausted, whatever medicines remain are completely eliminated.