As per the belief system of rebirth, an individual soul undergoes a number of births and deaths. In the religious scripture of Hindus, the Rig Veda ( 1500 BC – 1000 BC ), there is no mention of rebirth. So, the idea of rebirth may be alien to the Rig Vedic society.
But, when one reads the Hindu epic Mahabharat, one comes across the idea of rebirth. In Mahabharat, Arjuna killed Bhishma Pitamaha in a war of Kurukshetra by using Shikhandi as a shield. Knowing that Shikhandi was originally a woman in his / her previous birth, Bhishma Pitamaha would not attack her and thus get killed. Shikhandi was Amba in his previous life, who had taken rebirth to take revenge for an insult made by Bhishma Pitamaha.
It is said that the event of Mahabharat might have taken place around 800 BC. This was the Post Vedic period. This was the period of political state- small and big – formation in northern India. Political states were emerging gradually. These political states were led by the Kshatriya or warrior community. To expand their territory, Kshatriya needed the males to fight the enemy. War used to take place frequently between the different states to conquer each other’s territory.
War used to take place in the Rig Vedic period also. But, here, wars were taking place for the survival of life and not for the expansion of territory. But, now in the Post Vedic period, wars were fought to conquer and expand the territory. Normally people might have been reluctant to lose their precious life to conquer the territory for someone.
To solve the problem of getting the manpower easily to fight the war, the idea of rebirth might have originated. People might have been convinced that if they fight and get death in the war, they would get rebirth in better socio-economic conditions.
To conclude, the philosophical idea of rebirth instilled confidence in the general public to die or kill which might have solved the problem of territorial expansion.
