Srimad Bhagavatam Canto 01, Chapter 08, Text 51

SB 1.8.51

strinam mad-dhata-bandhunam
droho yo ’sav ihotthitah
karmabhir grhamedhiyair
naham kalpo vyapohitum
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
I have killed many friends of women, and I have thus caused enmity to such an extent that it is not possible to undo it by material welfare work.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
The grhamedhis are those whose only business is to perform welfare work for the sake of material prosperity. Such material prosperity is sometimes hampered by sinful activities, for the materialist is sure to commit sins, even unintentionally, in the course of discharging material duties. To get relief from such sinful reactions, the Vedas prescribe several kinds of sacrifices. It is said in the Vedas that by performing the asvamedha-yajña (horse sacrifice) one can get relief from even brahma-hatya (killing of a brahmana).
Yudhisthira Maharaja performed this asvamedha-yajña, but he thinks that even by performing such yajñas it is not possible to get relief from the great sins committed. In war either the husband or the brother or even the father or sons go to fight. And when they are killed, a fresh enmity is created, and thus a chain of actions and reactions increases which is not possible to be counteracted even by thousands of asvamedha-yajñas.
The way of work (karma) is like that. It creates one action and another reaction simultaneously and thus increases the chain of material activities, binding the performer in material bondage. In the Bhagavad-gita (9.27-28) the remedy is suggested that such actions and reactions of the path of work can be checked only when work is done on behalf of the Supreme Lord. The Battle of Kuruksetra was actually fought by the will of the Supreme Lord Sri Krsna, as it is evident from His version, and only by His will was Yudhisthira placed on the throne of Hastinapura. Therefore, factually no sin whatsoever touched the Pandavas, who were only the order carriers of the Lord. For others, who declare war out of personal interest, the whole responsibility lies on them.
Srimad Bhagavatam Canto 01, Chapter 08, Text 50
Srimad Bhagavatam Canto 01, Chapter 08, Text 52