Bhagavad-gītā As It Is · Text 17.15
Austerities of body, speech and mind
अनुद्वेगकरं वाक्यं सत्यं प्रियहितं च यत् ।
स्वाध्यायाभ्यसनं चैव वाङ्मयं तप उच्यते ॥ १५ ॥
anudvega-karaṁ vākyaṁ
satyaṁ priya-hitaṁ ca yat
svādhyāyābhyasanaṁ caiva
vāṅ-mayaṁ tapa ucyate
Austerity of speech consists in speaking words that are truthful, pleasing, beneficial, and not agitating to others, and also in regularly reciting Vedic literature.
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