Prabhupāda: Purport. Read on.
Devotee: "According to logicians, one has to take birth according to one's activities of life. After finishing one term of activities, one has to die to take birth for the next. In this way the cycle of birth and death is revolving, one after the other, without liberation. This cycle of birth and death does not, however, support unnecessary murder, slaughter and war unnecessarily. But at the same time, violence and war are inevitable factors in human society for keeping law and order. The Battle of Kurukṣetra, being the will of the Supreme, was an inevitable event, and to fight for the right cause is the duty of a kṣatriya. Why should he be afraid of or aggrieved at the death of his relatives since he was discharging his proper duty? He did not deserve to break the law, thereby becoming subjected to the reactions of sinful acts, of which he was so afraid. By ceasing from the discharge of his proper duty, he would not be able to stop the death of his relatives, and he would be degraded on account of his selection of the wrong path of action." 28: "All created beings are unmanifest in their beginnings, manifest in their interim state, and unmanifest again when they are annihilated. So what need is there for lamentation (BG 2.28)?" 29.
Prabhupāda: This another theory, that voidism, that before our, this manifested life, there was void, and after this manifestation is over, still there will be void. Because according to voidism, everything is manifested originally void. So Kṛṣṇa puts forward this argument that before this manifested form of life there was void, and after this manifested life, there will be void, according to the void philosophy. Then where is the cause of lamentation? There is no cause of lamentation. It was void and it is going to be void. So where is the cause of lamentation? But actually that is... Originally, it was not void. That is a Bhagavad-gītā and Vaiṣṇava theory.