[550] Therein, what is the awakening factor of concentration (samādhisambojjhaṅga)?
There is concentration (samādhi) with applied thought (vitakka) and with sustained thought (vicāra); there is concentration without applied thought and without sustained thought. Whatever concentration with applied thought and with sustained thought there is, that too is the awakening factor of concentration; it conduces to direct knowledge (abhiññā), to full awakening (sambodha), to Nibbāna. Whatever concentration without applied thought and without sustained thought there is, that too is the awakening factor of concentration; it conduces to direct knowledge, to full awakening, to Nibbāna.
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.