Pariññātasutta
There are these four dwellings of mindfulness.
What four?
Here a disciple dwells contemplating the body in the body, ardent, fully aware, mindful, having put away craving and aversion for the world.
For one dwelling contemplating the body in the body, the body becomes fully known.
Because of the body being fully known, the deathless is realized.
He dwells contemplating feelings in feelings, ardent, fully aware, mindful, having put away craving and aversion for the world.
For one dwelling contemplating feelings in feelings, feelings become fully known.
Because of feelings being fully known, the deathless is realized.
He dwells contemplating mind in mind, ardent, fully aware, mindful, having put away craving and aversion for the world.
For one dwelling contemplating mind in mind, the mind becomes fully known.
Because of the mind being fully known, the deathless is realized.
He dwells contemplating phenomena in phenomena, ardent, fully aware, mindful, having put away craving and aversion for the world.
For one dwelling contemplating phenomena in phenomena, phenomena become fully known.
Because of phenomena being fully known, the deathless is realized.