Vibhaṅgasutta
“Satipaṭṭhānañca vo, bhikkhave, desessāmi satipaṭṭhānabhāvanañca satipaṭṭhānabhāvanāgāminiñca paṭipadaṁ. Taṁ suṇātha. Katamañca, bhikkhave, satipaṭṭhānaṁ? Idha, bhikkhave, bhikkhu kāye kāyānupassī viharati ātāpī sampajāno satimā, vineyya loke abhijjhādomanassaṁ; vedanāsu vedanānupassī viharati …pe… citte cittānupassī viharati …pe… dhammesu dhammānupassī viharati ātāpī sampajāno satimā, vineyya loke abhijjhādomanassaṁ. Idaṁ vuccati, bhikkhave, satipaṭṭhānaṁ.
Analysis
“Mendicants, I will teach you mindfulness meditation, the development of mindfulness meditation, and the practice that leads to the development of mindfulness meditation. Listen … And what is mindfulness meditation? It’s when a mendicant meditates by observing an aspect of the body—keen, aware, and mindful, rid of covetousness and displeasure for the world. They meditate observing an aspect of feelings … mind … principles—keen, aware, and mindful, rid of covetousness and displeasure for the world. This is called mindfulness meditation.