The Bhagavad-gītā is spoken in the battlefield, and Arjuna was denying to fight, but Kṛṣṇa was asking him to fight. So the fighting was good, because it was the will of the Absolute Personality of Godhead. Therefore at the end of understanding Bhagavad-gītā, Arjuna agreed, "Yes, I shall fight."
So fighting for the matter of executing the desire of the Supreme Will is also absolute. It is not different from Absolute Truth. So sometimes it is . . . just like we sometimes see mock-fighting, because that fighting spirit is there. The father and son, the little son is fighting with the father. That is not fighting, but the mock fight. But the fighting spirit is there. You cannot deny it.
Similarly, the fighting spirit is there. Sometimes that is exhibited by the Supreme Personality of Godhead. And He wanted to exhibit such fighting spirit, so who will fight with Him? Ordinary living being cannot fight with the Supreme Lord. Therefore some of His devotees, some of His associates, must fight with Him.
Just like in the Bhagavad-gītā it is said that Arjuna was inquiring from Kṛṣṇa that, "You say that millions of years before, You spoke this Bhagavad-gītā yoga to the sun-god." Imaṁ vivasvate yogaṁ proktavān aham avyayam (BG 4.1). The Lord said that, "Many, many, many, many millions of years before, ago, I explained this science of Bhagavad-gītā to the sun-god." Now, to eliminate any doubts in the mind of ordinary persons like us, Arjuna inquired that, "Kṛṣṇa, You are my friend. We are almost of the same age. How do you say that You explained this Bhagavad-gītā millions and millions of years ago to the sun-god? How can I believe that?"