Verse
अनुद्वेगकरं वाक्यं सत्यं प्रियहितं च यत् ।स्वाध्यायाभ्यसनं चैव वाङ्मयं तप उच्यते ॥
anudvegakaraṃ vākyaṃ satyaṃ priyahitaṃ ca yatsvādhyāyābhyasanaṃ caiva vāṅmayaṃ tapa ucyate
Speech causing no trouble to others, true, kind and beneficial, the study of Scripture, are called the askesis of speech.
Gītā 17·15