To that which is born, death is certain; to that which is dead, birth is certain: be not afflicted by the unavoidable. As a noble whose duty it is to protect the law, refusing to fight this righteous war you will forfeit both virtue and honor. Your proper concern is alone the action (process) of duty, not the fruits (goals) of the action. Cast then away all desire and fear for the fruits, and perform your duty.

Bhagavad Gita
Krishna's teaching