At Savatthi. “Bhikkhus, there are these four establishments of mindfulness. What four? Here, bhikkhus, a bhikkhu dwells contemplating the body in the body, ardent, clearly comprehending, mindful, having removed covetousness and displeasure in regard to the world. sn.v.174 He dwells contemplating feelings in feelings … mind in mind … phenomena in phenomena, ardent, clearly comprehending, mindful, having removed covetousness and displeasure in regard to the world. These are the four establishments of mindfulness.”
SN47_24: Suddhasutta
Suddhasutta - translated by Bhikkhu Bodhi