When you slew your aged grandsire, you thought it your duty to do so. But when I have slain my wicked foe, why should it not be regarded as my duty?
पितामहं रणे हत्वा मन्यसे धर्ममात्मनः। मया शत्रौ हते कस्मात् पापे धर्मं न मन्यसे॥