[1246] Bhikkhus, it is because of having developed and cultivated the four bases for spiritual power (iddhipāda) that the Tathāgata has such great spiritual power, such great might. Which four? Here, bhikkhus, the Tathāgata develops the basis for spiritual power that possesses concentration (samādhi) due to desire (chanda) and volitional formations of striving (padhānasaṅkhāra), thus: 'My desire will be neither too slack nor too strained; 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 that possesses concentration due to energy … concentration due to mind … concentration due to inquiry (vīmaṃsā) and volitional formations of striving, thus: 'My inquiry will be neither too slack nor too strained …' Thus, with a mind that is open and unenveloped, he develops a mind imbued with luminosity. It is because of having developed and cultivated these four bases for spiritual power, bhikkhus, that the Tathāgata has such great spiritual power, such great might.
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.