A discourse of Swami Vivekananda on Mahabharata :
(Delivered at the Shakespeare Club, Pasadena, California, February 1, 1900)
The old Indian customs of the Kshatriyas were observed in it. Duryodhana took one side, Yudhishthira the other. From Yudhishthira messengers were at once sent to all the surrounding kings, entreating their alliance, since honourable men would grant the request that first reached them. So, warriors from all parts assembled to espouse the cause of either the Pandavas or the Kurus according to the precedence of their requests; and thus one brother joined this side, and the other that side, the father on one side, and the son on the other. The most curious thing was the code of war of those days; as soon as the battle for the day ceased and evening came, the opposing parties were good friends, even going to each other's tents; however, when the morning came, again they proceeded to fight each other. That was the strange trait that the Hindus carried down to the time of the Mohammedan invasion. Then again, a man on horseback must not strike one on foot; must not poison the weapon; must not vanquish the enemy in any unequal fight, or by dishonesty; and must never take undue advantage of another, and so on. If any deviated from these rules he would be covered with dishonour and shunned. The Kshatriyas were trained in that way. And when the foreign invasion came from Central Asia, the Hindus treated the invaders in the selfsame way. They defeated them several times, and on as many occasions sent them back to their homes with presents etc. The code laid down was that they must not usurp anybody's country; and when a man was beaten, he must be sent back to his country with due regard to his position. The Mohammedan conquerors treated the Hindu kings differently, and when they got them once, they destroyed them without remorse.
Mind you, in those days — in the times of our story, the poem says — the science of arms was not the mere use of bows and arrows at all; it was magic archery in which the use of Mantras, concentration, etc., played a prominent part. One man could fight millions of men and burn them at will. He could send one arrow, and it would rain thousands of arrows and thunder; he could make anything burn, and so on — it was all divine magic. One fact is most curious in both these poems — the Ramayana and the Mahabharata — along with these magic arrows and all these things going on, you see the cannon already in use. The cannon is an old, old thing, used by the Chinese and the Hindus. Upon the walls of the cities were hundreds of curious weapons made of hollow iron tubes, which filled with powder and ball would kill hundreds of men. The people believed that the Chinese, by magic, put the devil inside a hollow iron tube, and when they applied a little fire to a hole, the devil came out with a terrific noise and killed many people.