Uttarajjhayana 29.59

29.59

vaisamāhāraṇayāe ṇaṃ bhaṃte! jīve kiṃ jaṇayai?
vaisamāhāraṇayāe ṇaṃ vaisāhāraṇadadaṃsaṇapajjave visohei, visohettā sulahabohiyattaṃ nivvattei dullahabohiyattaṃ nijjarei|

“Sir, what does the soul produce through concentration of speech?”
“Through concentration of speech it purifies the modes of faith associated with speech; having purified [them], it achieves the condition of easily attained enlightenment and wears away the condition of difficultly attained enlightenment.”