Bhagavad Gita 1.36

निहत्य धार्तराष्ट्रान्न: का प्रीति: स्याज्ज्नार्दन |
पापमेवाश्रयेदसमान्हत्वैतानाततायिन:

Translation

O Maintainer of all living entities, what pleasure will we derive from killing the sons of Dhritarasthra? Even though they may be aggressors, sin will certainly come upon us if we slay them.