"We have to understand that fighting spirit is there in everyone. You cannot check it; you cannot stop it. We do not say stop. The Māyāvādī philosopher says that 'You stop this thing.' But that is not possible. You cannot stop. Because you are living entity, you have got all these propensities. How you can stop it? But it should be utilized properly. That's all.
You have got the fighting spirit. How to utilize it? Yes. Narottama dāsa Ṭhākura recommends, 'krodha' bhakta-dveṣī-jane: 'Those who are envious of God or God's devotee, you can utilize your anger upon them.' You can utilize. The anger you cannot give up. Our business is how to utilize it. That is Kṛṣṇa consciousness. Everything has to be utilized. We do not say that 'You stop this, stop that.' No. Kṛṣṇa says, yat karoṣi, yaj juhosi, yad aśnāsi, yat tapasyasi kuruśva tad mad-arpanam (BG 9.27). Yat karoṣi. Kṛṣṇa does not say that 'You do this, you do that.' He says, 'Whatever you do, but the result should come to Me.'
So here the position is that Arjuna is to fight not for himself, but he is only thinking in terms of himself. He says, te avasthitaḥ pramukhe dhārtarāṣṭrāḥ, yān eva hatvā na jijīviṣāmas (BG 2.6): 'They are my brothers, relatives. If they die... We do not wish to die. Now they are in my front. I have to kill them?' So still he is thinking in terms of his own satisfaction. He is preparing the background—how materialistic person, they think in the terms of personal satisfaction. So that has to be given up. Not personal satisfaction, Kṛṣṇa's satisfaction. That is Kṛṣṇa consciousness. Whatever you do, it doesn't matter, you have to test it whether you are doing it for Kṛṣṇa. That is your perfection. Not only perfection, that is the perfection of your mission of human life."
(Srila Prabhupada Lecture, London, August 6, 1973)