T 1670B Nāgasena Bhikṣu Sūtra
Part 2: Dialogues
2.42. On Nirvana
The king asked Nāgasena, “What is nirvana? Is it that all having gone past, there will be no more becoming?”
Nāgasena replied, “Nirvana is that in which there is no more becoming. Ignorant people come yearning for and craving for (the sense pleasures of) the inner and outer bodies.
Therefore they are not set free from old age, sickness and death.” Nāgasena continued, “Wise men, those who have learned the Dharma, do not cling to the internal and external pleasures of the body, and also have no craving. Having no craving, they have no sense desire. Having no sense desire, they have no pregnancy. Having no pregnancy, there is no birth and no old age. Having no birth and no old age, there is no sickness and no death. Having no sickness (and no death), they have no grief, no lamentation; having no grief and no lamentation, they have no inner pain, they thus obtain nirvana.”