Bhagavad Gita 1-37, 38

yadyapyEtE na pashyaMti lObhOpahataachEtasaHa

kulakShyakRutaM dOShaM mitradrOhE cha pAtakaM || 37 ||

kathaM na jnEyamasmAbhiHi pApAdasmAnnivartituM

kulakShayakRutaM dOshaM prapashyadbhirjanArdhana || 38 ||

Their hearts are completely influenced by greed that they are unable to see the sins of extinction of the family and deceiving their friends. But oh Janardhana, we are able to foresee and understand the sins of extinction of the family why can't we refrain from this war?

Arjuna says that the hearts of Kauravas are completely overtaken by the greed which has blinded their thought process and has perished their ability to see the dire consequences of their action. They are unable to perceive the sins they are committing by deceiving their own friends and killing their entire family. But we unlike them are able to foresee all these terrible consequences of fighting the war with our own people. This will literally result in extinction of entire dynasty. When we can foresee and are aware, is it right on our part in this terrible war. Is it not sinful to commit a mistake when you are completely aware of its consequences?

This is an excellent argument by Arjuna that we have to keep in mind the consequences when we act. Whether the act itself is correct or not will be decided not by the action but by the expected consequences. Most of us think the same way. We always think about the consequences of our action before we act. This is ingrained even in our judicial system. A person with no ability or reduced ability to be aware of the consequences of his/her action may have a reduced sentence or even be freed. Intent rather than the action becomes more important. In this sense it makes sense to us when Arjuna says that we refrain from the war when we are aware of the terrible consequences the war is going to bring up on us.