[515] And how does a bhikkhu develop the basis for success (iddhipāda) endowed with concentration due to investigation and volitional formations of striving?
If a bhikkhu, having made investigation (vīmaṃsā) predominant, gains concentration (samādhi), gains one-pointedness of mind (cittassa ekaggatā), this is called concentration due to investigation. He generates zeal (chanda), endeavours, arouses energy, exerts his mind, and strives for the non-arising of unarisen evil, unwholesome phenomena (dhammā); for the abandoning of arisen evil, unwholesome phenomena …; for the arising of unarisen wholesome phenomena …; he generates zeal, endeavours, arouses energy, exerts his mind, and strives for the persistence, non-loss, increase, abundance, development, and fulfilment of arisen wholesome phenomena. These are called volitional formations of striving (padhāna-saṅkhārā).
Thus this concentration due to investigation and these volitional formations of striving, gathered together and condensed into one, come to be reckoned simply as "concentration due to investigation with volitional formations of striving" (vīmaṃsā-samādhi-padhāna-saṅkhāra).
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.