Bhāvanāsutta
“Catunnaṁ, bhikkhave, satipaṭṭhānānaṁ bhāvanaṁ desessāmi. Taṁ suṇātha. Katamā, bhikkhave, catunnaṁ satipaṭṭhānānaṁ bhāvanā? Idha, bhikkhave, bhikkhu kāye kāyānupassī viharati ātāpī sampajāno satimā, vineyya loke abhijjhādomanassaṁ; vedanāsu …pe… citte …pe… dhammesu dhammānupassī viharati ātāpī sampajāno satimā, vineyya loke abhijjhādomanassaṁ. Ayaṁ kho, bhikkhave, catunnaṁ satipaṭṭhānānaṁ bhāvanā”ti.
Development
“Mendicants, I will teach you the development of the four kinds of mindfulness meditation. Listen … And what is the development of the four kinds of 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 the development of the four kinds of mindfulness meditation.”