Translated from Taishō Tripiṭaka volume 2, number 99
Thus have I heard. At one time the Buddha was abiding in Śrāvastī, in the Jeta Grove, in Anāthapiṇḍada’s Park. Then Venerable Ānanda along with an assembly of many bhikṣus went to the place of the Bhagavān, paid obeisance at his feet, and then sat off to one side. Venerable Ānanda addressed the Buddha, saying, “Bhagavān, what should these young bhikṣus be taught? How should the Dharma be spoken to them?”
The Buddha said to Ānanda, “These young bhikṣus should be taught the Four Bases of Mindfulness, causing them to be cultivated. What are these four? That is to say, [1] abiding in mindfulness of the body, observing the body: ardent, vigilant, mindful and aware, quieted in mind, even fully knowing the body; [2] and abiding in mindfulness of sensations; [3] of the mind; [4] and of dharmas, observing dharmas: ardent, vigilant, mindful and aware, quieted in mind, even fully knowing dharmas. For what reason?
“If a bhikṣu is dwelling at the ground of study, and who has not yet attained advancement, but has resolved to seek the peaceful tranquility of Nirvāṇa, [1] he abides in mindfulness of the body, observing the body: ardent, vigilant, mindful and aware, quieted in mind; [2] and of sensations; [3] and of the mind; [4] and abiding in mindfulness of dharmas, observing dharmas: ardent, vigilant, mindful and aware, quieted in mind, even fully detached from dharmas.
“If there is an arhat, with outflows dried up, who has done what was to be done, who has abandoned the burden, who has exhausted his fetters, and correctly known liberation: he also at that time still [1] abides in mindfulness of the body, observing the body: ardent, vigilant, mindful and aware, quieted in mind; [2] and of sensations; [3] and of the mind; [4] and abiding in mindfulness of dharmas, observing dharmas, even fully detached from dharmas.”
Then Venerable Ānanda joyfully paid his respects and departed.