Trường Bộ Kinh (Digha Nikaya) 2:109
SUJATO‘Atthi cittan’ti vā panassa sati paccupaṭṭhitā hoti yāvadeva ñāṇamattāya paṭissatimattāya anissito ca viharati, na ca kiñci loke upādiyati.
Or mindfulness is established that the mind exists, to the extent necessary for knowledge and mindfulness. They meditate independent, not grasping at anything in the world.