Sotasutta 9.2

9.2

Idha, bhikkhave, bhikkhu tathāgatappavedite dhammavinaye desiyamāne aṭṭhiṅkatvā manasi katvā sabbaṃ cetasā samannāharitvā ohitasoto dhammaṃ suṇāti.

It’s when a mendicant pays attention, applies the mind, concentrates wholeheartedly, and actively listens when the teaching and training proclaimed by a Realized One is being taught.