1The Blessed One then said to the Venerable Ānanda: "Ānanda, what now is spiritual power? What is the basis for spiritual power? What is the development of the bases for spiritual power? What is the way leading to the development of the bases for spiritual power?"
The Buddha answers his own questions exactly as in §19. sn.v.287

1Ekamantaṁ nisinnaṁ kho āyasmantaṁ Ānandaṁ bhagavā etadavoca: "katamā nu kho, Ānanda, iddhi, katamo iddhipādo, katamā iddhi pāda bhāvanā, katamā iddhi pāda bhāvanāgāminī paṭipadā"ti? Bhagavaṁmūlakā no, bhante, dhammā bhagavaṁnettikā … pe … .

2"Idhānanda, bhikkhu anekavihitaṁ iddhividhaṁ paccanubhoti – ekopi hutvā bahudhā hoti … pe … yāva brahmalokāpi kāyena vasaṁ vatteti – ayaṁ vuccatānanda, iddhi.

3Katamo cānanda, iddhipādo? Yo, Ānanda, maggo yā paṭipadā iddhilābhāya iddhipaṭilābhāya saṁvattati – ayaṁ vuccatānanda, iddhipādo.

4Katamā cānanda, iddhi pāda bhāvanā? Idhānanda, bhikkhu chandasamādhippadhānasaṅkhārasamannāgataṁ iddhi pādaṁ bhāveti, vīriyasamādhi … pe … cittasamādhi … vīmaṁsāsamādhippadhānasaṅkhārasamannāgataṁ iddhi pādaṁ bhāveti – ayaṁ vuccatānanda, iddhi pāda bhāvanā.

5Katamā cānanda, iddhi pāda bhāvanāgāminī paṭipadā? Ayameva ariyo aṭṭhaṅgiko maggo, seyyathidaṁ – sammādiṭṭhi … pe … sammāsamādhi – ayaṁ vuccatānanda, iddhi pāda bhāvanāgāminī paṭipadā"ti.

Aṭṭhamaṁ.