This particular field on which the war was about to be fought had historically been a sacred place, where sacrifices and other sacred and auspicious acts had been performed. At the same time, it was also the place where the dynasty that sprouted the hundred wicked brothers had engaged in its nefarious activities. Therefore, this field was both sacred and corrupted by evil. This field is symbolic of the human body.
When a body is born it is pure and unblemished; it is not a victim of any of the six enemies of man: desire, anger, greed, infatuation, pride and jealousy. A new-born baby is naturally joyful. Whoever may look at it, whether that person is a thief or a king, the baby is happy. It smiles and laughs at anyone who comes towards it, whether that person has come to kiss it or beat it. Since a small child is
pure, its body can be described as the field of righteousness. As the body grows, it goes on collecting bad qualities, such as jealousy, hatred, attachment, greed, selfishness. As these evil traits
accumulate, the body becomes impure. Therefore, the body can be considered both pure and impure. Good and bad are both encased in your heart.
The impure qualities are associated with my-ness, the possessive tendency. The inner significance of this battle between the forces of good and evil, with the five Pandava brothers and Krishna on one side, and the 100 wicked Kaurava brothers on the other side, is the inner war taking place in each individual, an all-out war between good and bad, between righteousness and immorality, between selflessness and selfishness.
The Kaurava brothers represent those people who consider things which do not belong to them as their own. They represent the possessive nature. They consider the body as their very self. If you observe people of the Kaurava mentality, that is, those having this possessive attitude, you will find that they all identify themselves with the body and the senses. The great war between the Pandavas and the Kauravas lasted only eighteen days, but the war between the forces of good and evil goes on throughout your life. It has no end. This battle is fought in the field of your own body. In this way, Krishna explained some of the deeper significance of the war to Arjuna.