4.
The Discourse on Disenchantment
816.
"Monks, these four bases for spiritual power, when developed and cultivated, lead exclusively to disenchantment, to dispassion, to cessation, to peace, to direct knowledge, to highest enlightenment, to Nibbāna.
Which four?
Here, monks, a monk develops the basis for spiritual power that possesses concentration due to desire and volitional activities of striving, concentration due to energy, etc.
concentration due to mind, etc.
develops the basis for spiritual power that possesses concentration due to investigation and volitional activities of striving.
These, monks, are the four bases for spiritual power which, when developed and cultivated, lead exclusively to disenchantment, to dispassion, to cessation, to peace, to direct knowledge, to highest enlightenment, to Nibbāna."
The fourth.