[132] "But, venerable sir, what is the cause, what is the condition, for the purification of beings? How is it that beings are purified with cause, with condition?"
"Mahāli, if this form (rūpa) were exclusively pleasurable, followed by pleasure, steeped in pleasure, and not steeped in suffering (dukkha), beings would not become disenchanted with form. But, Mahāli, because form is suffering, followed by suffering, steeped in suffering, and not steeped in pleasure, therefore beings become disenchanted with form; being disenchanted, they become dispassionate; through dispassion they are purified. This too, Mahāli, is a cause, this is a condition, for the purification of beings. Thus too beings are purified with cause, with condition.
"And, Mahāli, if this feeling (vedanā) were exclusively pleasurable … And if this perception (saññā), Mahāli … And, Mahāli, if these volitional formations (saṅkhārā) were exclusively pleasurable … And, Mahāli, if this consciousness (viññāṇa) were exclusively pleasurable, followed by pleasure, steeped in pleasure, and not steeped in suffering, beings would not become disenchanted with consciousness. But, Mahāli, because consciousness is suffering, followed by suffering, steeped in suffering, and not steeped in pleasure, therefore beings become disenchanted with consciousness; being disenchanted, they become dispassionate; through dispassion they are purified. This too, Mahāli, is a cause, this is a condition, for the purification of beings. Thus too beings are purified with cause, with condition."
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.