Trung Bộ Kinh (Majjhima Nikaya) 3:111
SUJATOYasmiṁ samaye, bhikkhave, bhikkhu tathāsato viharanto taṁ dhammaṁ paññāya pavicinati pavicayati parivīmaṁsaṁ āpajjati, dhammavicayasambojjhaṅgo tasmiṁ samaye bhikkhuno āraddho hoti, dhammavicayasambojjhaṅgaṁ tasmiṁ samaye bhikkhu bhāveti, dhammavicayasambojjhaṅgo tasmiṁ samaye bhikkhuno bhāvanāpāripūriṁ gacchati.
At such a time, a mendicant has activated the awakening factor of investigation of principles; they develop it and perfect it.