sn36.31:8.2 Idha, bhikkhave, bhikkhu sukhassa ca pahānā, dukkhassa ca pahānā, pubbeva somanassadomanassānaṁ atthaṅgamā, adukkhamasukhaṁ upekkhāsatipārisuddhiṁ catutthaṁ jhānaṁ upasampajja viharati.