[170] Therein, what is right concentration (sammāsamādhi)?
Here a bhikkhu, quite secluded from sensual pleasures, secluded from unwholesome phenomena (akusalā dhammā), enters and dwells in the first jhāna, which is accompanied by thought (vitakka) and examination (vicāra), with rapture (pīti) and pleasure born of seclusion. With the stilling of thought and examination, he enters and dwells in the second jhāna, which has internal confidence and unification of mind, is without thought, without examination, with rapture and pleasure born of concentration (samādhi). With the fading away of rapture, he dwells equanimous (upekkhako) and, mindful (sato) and clearly comprehending (sampajāno), he experiences pleasure with the body; he enters and dwells in the third jhāna, of which the noble ones declare: "He is equanimous, mindful, one who dwells happily." With the abandoning of pleasure and the abandoning of pain, and with the previous passing away of joy and grief, he enters and dwells in the fourth jhāna, which is neither-painful-nor-pleasant and has purity of mindfulness due to equanimity. This is called right concentration.
This is called the noble truth of the way of practice leading to the cessation of suffering (dukkhanirodhagāminī paṭipadā ariyasaccaṃ).
The Suttanta Analysis (Suttantabhājanīya).
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.