Bhagwad Gita
Chapter 1, Verse 36
निहत्य धार्तराष्ट्रान्नः का प्रीतिः स्याज्जनार्दन।
पापमेवाश्रयेदस्मान्हत्वैतानाततायिनः।।1.36।।
Sin will overcome us if we slay such aggressors. Therefore it is not proper for us to kill the sons of Dhrtarastra and our friends. What should we gain, O Krsna, husband of the goddess of fortune, and how could we be happy by killing our own kinsmen?