Our ancient texts say that a nation can progress only when its people are protected. This means that every citizen must feel secure and protected. It is the security forces of a nation that provides this protection. An army is necessary not only to defend a nation against invaders but also to maintain a stable administration and discipline in the society.
The history of ancient India is largely a history of culture. Tribes forms societies and societies became civilizations with rich Cultural Heritage and a well organised system of governance. Pastoral society of the early vedic age got transformed into settled Agrarian society in the later vedic period. The 'King' or the leader of the tribe was called "Gopati" (lord of cattle) and later as "Bhupati" (lord of the land). Bows and arrows used for hunting became weapons of war. As societies changed so did the armies and the weapons they used.
The life of people is conditioned by the geography of their habitat. Indian history mentions Harappan civilization to be around 2600 B.C-1900 B.C, based on excavations and other evidences. The people of Harappa and Mohanjodaro settled around the 'Indus' river and did not have any boundaries around their land. But after its decline and disappearance, settlers from the West and North West started settling Tribes, being agriculturists, started cultivating land for crops and these lands were marked with boundaries called 'Janapadas'.
The family was the basic unit of the Rig Vedic society. The group consisting of families was called 'Clan' and one or more Clans were called 'Jana' or tribe. As the tribes became bigger with more population the requirement of land became larger and bigger boundaries were formed. This was the first boundary created and the tribes protected their land from animals and other tribes. Some tribes migrated to different parts of India and in this process came in contact with other tribes thus resulting in conflicts and wars.
What happens when tribes migrate to other places and want to live with those already settled in those areas? It results in rivalry, conflicts and ultimately wars. The expanding and migrating tribes created larger boundaries of their land and needed separate men to protect their land, livestock and people. They formed armies from among physically strong and capable men to protect it. As tribes became bigger, they settled down and formed societies and created laws of marriage and property. They chose a leader who was named a 'Bhupati' and later called a King.
Societies faced threat from burglars and others who would steal cattle among other things. It was also a custom to seek the hand of a princess in marriage by proving one's strength or ability to be superior. If marriage was denied it resulted in fights. People generally fought with each other on three major issues; of capture of territory and wealth, in retaliation to cattle lifting and on refusal of marriage with the woman of another tribe.
The early vedic society did not have any caste system. Occupation was not based on birth but based on skills and natural flair for a particular activity. However, chiefs, priests and warriors existed. In early vedic period, the 'sena' or army was not a permanent fighting group but consisted of able bodied tribesmen who were mobilized at the time of conflict with others. Migration and pressures of population made them change from a peace loving agri-society to being warlike.
As societies settled into larger groups they formed laws of marriage, property, etc. A settled society also witnessed a transformation of how people were assigned specific work within the society, as per their capability. To ensure social harmony the people of a Clan were divided into communities based on the work they were doing. For e.g. a farmer, carpenter, trader became Vaisyas, while a priest became a brahmin.
Similarly, a man selected to be a warrior became a Kshatriya. This was called the "Varna System" of society. As laws became stricter and population grew, there was a need to have one central authority to enforce discipline. Thus was framed "Dandaniti" - laws for the society. The enforcer was the Dandadara or the King who was assisted by the army.
It was logical that with Stringent laws there was a need for enforcement of the law. In the Varna system the Kshatriyas became the rulers and warriors. Our ancestors understood the value and importance of the army. Wars were fought for many reasons which were psychological in nature such as showing heroism, seeking glory on, being martyred, etc.
History is full of examples of war between the strong and the weak. Therefore, the expansion of societies created conditions for fighting between tribes which in turn required the need for creation of a separate caste to be soldiers. This dual condition necessitated the thought process that even during peace time, an army had to be maintained. Thus we came across the term called 'standing army'. This standing army consisted of the 'Kshatriya' or the warrior community and fighting and dying for the King became their "swadharma".
The warriors soon emerged as a special class within the society which looked upon this community as the protectors and saviours of their land. The people did not mind the high position in society for the warrior class.