Kṛṣṇa was encouraging to fight; Arjuna was also very intelligently replying. He addressed Kṛṣṇa as Madhusūdana, Arisūdana. Madhusūdana means "The killer of Madhu demon," or "The killer of enemy." So his purpose is that, "I have to kill Bhīṣmadeva, who is my so kind grandfather, and I have to kill Droṇācārya, who is my teacher, from whom I have learned this military art.
So You have killed the demons and Your enemy, and why You are inducing me to kill my guru and my grandfather?" This is his argument. Kathaṁ bhīṣmam ahaṁ saṅkhye droṇaṁ ca madhusūdana, iṣubhiḥ pratiyotsyāmi (BG 2.4): "They, my grandfather, my teacher, may chastise me, but how I can pierce with arrows their body?"
So this is the problem, duty. Arjuna was forgetting duty. And Kṛṣṇa was inducing him: "Never mind. According to kṣatriya rules and regulation, even the opposite party is your own son, you should not hesitate to kill him. This is kṣatriya's business." If the opposite party is your own son, but when there is fight, there must be decided: one party must be killed. This is kṣatriya's business.
So he says, gurūn ahatvā hi mahānubhāvān (BG 2.5). "These guru, this Droṇācārya and Bhīṣma, they are not ordinary men." Mahānubhāvān. Bhīṣma, everyone knows. Bhīṣma is one of the authorities, authorities of religious principle. There are twelve authorities.
- svayambhūr nāradaḥ śambhuḥ
- kumāraḥ kapilo manuḥ
- prahlādo janako bhīṣmo
- balir vaiyāsakir vayam
- (SB 6.3.20)