One verse

Bhagavad Gita 17.15

17.15

अनुद्वेगकरं वाक्यं सत्यं प्रियहितं च यत् | स्वाध्यायाभ्यसनं चैव वाङ्मयं तप उच्यते ||१७-१५||

anudvegakaraṃ vākyaṃ satyaṃ priyahitaṃ ca yat . svādhyāyābhyasanaṃ caiva vāṅmayaṃ tapa ucyate ||17-15||

anudvega-karam
not agitating
vākyam
words
satyam
truthful
priya
dear
hitam
beneficial
ca
also
yat
which
svādhyāya
of Vedic study
abhyasanam
practice
ca
also
eva
certainly
vāk-mayam
of the voice
tapaḥ
austerity
ucyate
is said to be

Austerity of speech consists in speaking words that are truthful, pleasing, beneficial, and not agitating to others, and also in regularly reciting Vedic literature.