Saṃyutta Nikāya 47
Connected Discourses on the Establishments of Mindfulness
36. Final Knowledge
“Bhikkhus, there are these four establishments of mindfulness. What four? Here, bhikkhus, a bhikkhu dwells contemplating the body in the body … feelings in feelings … mind in mind … phenomena in phenomena, ardent, clearly comprehending, mindful, having removed covetousness and displeasure in regard to the world.
“When, bhikkhus, these four establishments of mindfulness have been developed and cultivated, one of two fruits may be expected: either final knowledge in this very life or, if there is a residue of clinging, the state of nonreturning.”