[1179] Bhikkhus, these four bases for spiritual power (iddhipāda), when developed and cultivated, are of great fruit and great benefit. And how, bhikkhus, are the four bases for spiritual power developed, how cultivated, so that they are of great fruit and great benefit? Here, bhikkhus, a bhikkhu develops the basis for spiritual power endowed with concentration (samādhi) due to desire (chanda) and volitional formations of striving (padhānasaṅkhāra), thinking: 'Thus my desire will be neither too slack nor too tense; and it will be neither constricted internally nor distracted externally.' And he dwells percipient of after and before: 'As before, so after; as after, so before; as below, so above; as above, so below; as by day, so by night; as by night, so by day.' Thus, with a mind (citta) that is open and unenveloped, he develops a mind imbued with luminosity. He develops the basis for spiritual power endowed with concentration due to energy … concentration due to mind … concentration due to inquiry (vīmaṃsā) and volitional formations of striving, thinking: 'Thus my inquiry will be neither too slack nor too tense; and it will be neither constricted internally nor distracted externally.' And he dwells percipient of after and before: 'As before, so after; as after, so before; as below, so above; as above, so below; as by day, so by night; as by night, so by day.' Thus, with a mind that is open and unenveloped, he develops a mind imbued with luminosity.
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.