Srimad Bhagavatam Canto 01, Chapter 08, Text 49

SB 1.8.49

bala-dvija-suhrn-mitra-
pitr-bhratr-guru-druhah
na me syan nirayan mokso
hy api varsayutayutaih
 
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
I have killed many boys, brahmanas, well-wishers, friends, parents, preceptors and brothers. Though I live millions of years, I will not be relieved from the hell that awaits me for all these sins.
 
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
Whenever there is a war, there is certainly a massacre of many innocent living beings, such as boys, brahmanas and women, whose killing is considered to be the greatest of sins. They are all innocent creatures, and in all circumstances killing of them is forbidden in the scriptures. Maharaja Yudhisthira was aware of these mass killings. Similarly, there were friends, parents and preceptors also on both sides, and all of them were killed. It was simply horrible for him to think of such killing, and therefore he was thinking of residing in hell for millions and billions of years.
Srimad Bhagavatam Canto 01, Chapter 08, Text 48
Srimad Bhagavatam Canto 01, Chapter 08, Text 50