The Battle of Kurukṣetra was fought between family members, and thus all affected persons were also family members like Mahārāja Yudhiṣṭhira and brothers, Kuntī, Draupadī, Subhadrā, Dhṛtarāṣṭra, Gāndhārī and her daughters-in-law, etc.
(Srimad Bhagavatam-----1:8:3-----purport).

When the Lord saw that there was no time for the Pāṇḍavas to counteract the brahmāstra of Aśvatthāmā, He took up His weapon even at the risk of breaking His own vow. Although the Battle of Kurukṣetra was almost finished, still, according to His vow, He should not have taken up His own weapon. But the emergency was more important than the vow. He is better known as the bhakta-vatsala, or the lover of His devotee, and thus He preferred to continue as bhakta-vatsala than to be a worldly moralist who never breaks his solemn vow.
(Srimad Bhagavatam-----1:8:13-----purport).

Both the sons of Dhṛtarāṣṭra and those of Pāṇḍu belonged to the same dynasty of Mahārāja Kuru; therefore both of them were generally known as Kurus. But when there were differences between the two families, the sons of Dhṛtarāṣṭra were known as Kurus whereas the sons of Pāṇḍu were known as Pāṇḍavas. Since the sons and grandsons of Dhṛtarāṣṭra were all killed in the Battle of Kurukṣetra, the last son of the dynasty is designated as the son of the Kurus.
(Srimad Bhagavatam-----1:8:14-----purport).

Similarly, when they were exiled in the forest, Bhīma had to fight with the man-eater demon Hiḍimbā Rākṣasa, but the Lord saved him. So it was not finished there. After all these tribulations, there was the great Battle of Kurukṣetra, and Arjuna had to meet such great generals as Droṇa, Bhīṣma and Karṇa, all powerful fighters. And at last, even when everything was done away with, there was the brahmāstra released by the son of Droṇācārya to kill the child within the womb of Uttarā, and so the Lord saved the only surviving descendant of the Kurus, Mahārāja Parīkṣit.
(Srimad Bhagavatam-----1:8:24-----purport).

When the Lord descends on this material world by His all-merciful energy, He plays like a human being, and therefore it appears that the Lord is partial to His devotees only, but that is not a fact. Despite such apparent manifestation of partiality, His mercy is equally distributed. In the Battlefield of Kurukṣetra all persons who died in the fight before the presence of the Lord got salvation without the necessary qualifications because death before the presence of the Lord purifies the passing soul from the effects of all sins, and therefore the dying man gets a place somewhere in the transcendental abode.
(Srimad Bhagavatam-----1:8:29-----purport).

The lessons of the Bhagavad-gītā and all the Purāṇas, specifically the Bhāgavata Purāṇa, are therefore inevitably connected with the history of the Pāṇḍava mahātmās. For them, separation from the Lord was just like the separation of a fish from water. Śrīmatī Kuntīdevī, therefore, felt such separation like a thunderbolt, and the whole prayer of the Queen is to try to persuade the Lord to stay with them. After the Battle of Kurukṣetra, although the inimical kings were killed, their sons and grandsons were still there to deal with the Pāṇḍavas. It is not only the Pāṇḍavas who were put into the condition of enmity, but all of us are always in such a condition, and the best way of living is to become completely dependent on the will of the Lord and thereby overcome all difficulties of material existence.
(Srimad Bhagavatam-----1:8:37-----purport).

The whole clique of politics centered around this point, and all the kings and residents of the whole world became involved in this fight between the rival brothers. Lord Kṛṣṇa was also there on the side of King Yudhiṣṭhira. It is said in the Mahābhārata (Ādi-parva 2.25) that 640,000,000 men were killed in the eighteen days of the Battle of Kurukṣetra, and millions were missing. Practically this was the greatest battle in the world within five thousand years.
(Srimad Bhagavatam-----1:8:46-----purport).

A solid phalanx of 21,870 chariots, 21,870 elephants, 109,650 infantry and 65,600 cavalry is called an akṣauhiṇī. And many akṣauhiṇīs were killed on the Battlefield of Kurukṣetra. Mahārāja Yudhiṣṭhira, as the most pious king of the world, takes for himself the responsibility for killing such a huge number of living beings because the battle was fought to reinstate him on the throne. This body is, after all, meant for others. While there is life in the body, it is meant for the service of others, and when it is dead it is meant to be eaten by dogs and jackals or maggots. He is sorry because for such a temporary body such a huge massacre was committed.
(Srimad Bhagavatam-----1:8:48-----purport).

The way of work (karma) is like that. It creates one action and another reaction simultaneously and thus increases the chain of material activities, binding the performer in material bondage. In the Bhagavad-gītā (Bg. 9.27-28) the remedy is suggested that such actions and reactions of the path of work can be checked only when work is done on behalf of the Supreme Lord. The Battle of Kurukṣetra was actually fought by the will of the Supreme Lord Śrī Kṛṣṇa, as it is evident from His version, and only by His will was Yudhiṣṭhira placed on the throne of Hastināpura. Therefore, factually no sin whatsoever touched the Pāṇḍavas, who were only the order carriers of the Lord. For others, who declare war out of personal interest, the whole responsibility lies on them.
(Srimad Bhagavatam-----1:8:51-----purport).

By the order of his mother, Satyavatī, who was later married to Mahārāja Śantanu, and by the request of Bhīṣmadeva, the eldest son of Mahārāja Śantanu by his first wife, the Ganges, he begot three brilliant sons, whose names are Dhṛtarāṣṭra, Pāṇḍu and Vidura. The Mahābhārata was compiled by Vyāsadeva after the Battle of Kurukṣetra and after the death of all the heroes of Mahābhārata. It was first spoken in the royal assembly of Mahārāja Janamejaya, the son of Mahārāja Parīkṣit.
(Srimad Bhagavatam-----1:9:6-7-----purport).

Vasiṣṭha: The great celebrated sage among the brāhmaṇas, well known as the Brahmarṣi Vasiṣṭhadeva. He is a prominent figure in both the Rāmāyaṇa and Mahābhārata periods. He celebrated the coronation ceremony of the Personality of Godhead Śrī Rāma. He was present also on the Battlefield of Kurukṣetra. He could approach all the higher and lower planets, and his name is also connected with the history of Hiraṇyakaśipu. There was a great tension between him and Viśvāmitra, who wanted his kāmadhenu, wish-fulfilling cow. Vasiṣṭha Muni refused to spare his kāmadhenu, and for this Viśvāmitra killed his one hundred sons. As a perfect brāhmaṇa he tolerated all the taunts of Viśvāmitra.
(Srimad Bhagavatam-----1:9:6-7-----purport).

Mahārāja Yudhiṣṭhira was disturbed due to the great massacre in the Battle of Kurukṣetra. Bhīṣmadeva could understand this, and therefore he spoke first of the terrible sufferings of Mahārāja Yudhiṣṭhira. He was put into difficulty by injustice only, and the Battle of Kurukṣetra was fought just to counteract this injustice. Therefore, he should not regret the great massacre. He wanted to point out particularly that they were always protected by the brāhmaṇas, the Lord and religious principles.
(Srimad Bhagavatam-----1:9:12-----purport).