There are two verses on this subject. One following this mode of life, should address all creatures with words of affection, and pleasant to the cars. To give pain, to inflict tortures, and use harsh words, are all censurable.
श्लोकौ चात्र भवतः-वात्सल्यात्सर्वभूतेभ्यो वाच्याः श्रोत्रसुखा गिरः। परितापोपघातश्च पारुष्यं चात्र गर्हितम्॥