1-12.
The Set of Twelve Discourses Beginning with the Ganges River
845-856.
"Just as, monks, the river Ganges slants towards the east, slopes towards the east, inclines towards the east;
so too, monks, a monk developing the four bases for spiritual power, cultivating the four bases for spiritual power, slants towards Nibbāna, slopes towards Nibbāna, inclines towards Nibbāna.
And how, monks, does a monk developing the four bases for spiritual power, cultivating the four bases for spiritual power, slant towards Nibbāna, slope towards Nibbāna, incline towards Nibbāna?
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.
"Thus, monks, a monk developing the four bases for spiritual power, cultivating the four bases for spiritual power, slants towards Nibbāna, slopes towards Nibbāna, inclines towards Nibbāna." The twelfth.