Trung Bộ Kinh (Majjhima Nikaya) 3:126
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.
investigation of principles …