They should be humble in speech, but their hearts must be as sharp as the razors. When you are engaged in doing a very cruel and terrible act, you should talk with smiles on your lips.
वाचा भृशं विनीतः स्याद्धदयेन तथा क्षुरः। स्मितपूर्वाभिभाषी स्यात् सृष्टो रौद्राय कर्मणे॥