[1139] He develops the basis for spiritual power (iddhipāda) that possesses concentration due to mind (cittasamādhi) and volitional formations of striving (padhānasaṅkhāra), thinking: "Thus my mind (citta) will be neither too slack nor too tense; and it will be neither constricted internally nor distracted externally." And he dwells perceiving 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 the mind imbued with luminosity.
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.