I am not this body. I am soul. I am spirit soul. There are so many evidences. If I am this body, then when the soul is not there, the living entity is not there, the body is simply a lump of matter. That is the difference between a dead body and living body. Living body means that the soul is there, therefore the body is moving. And as soon as the soul is not there, the body is nothing but a lump of matter. I think somebody as my father. I call, "Father," father immediately replies, "Yes, my son." But when the soul of the father is not there, then the father, this body of the father whom I am seeing as father, although he is there, still he cannot reply. This is the distinction.
So Kṛṣṇa is replying that "You are afraid of fighting with your kinsmen, but you are mistaken. You are mistaken." Every one of us is mistaken, because there are four defects in our conditional life. This is our conditional life. So long we are within this body, material body, that is our conditional life. We live under certain conditions. But actually, we are spirit soul, we are part and parcel of God. As soon as we are free from this conditional life, that is our real, actual life. That is called liberated life.
The human form of life is meant for getting this liberation. So long one does not get this human form of life by the evolutionary process . . . there is evolution, from aquatic to birds and beast and then . . . jalajā nava-lakṣāṇi (Padma Purāṇa). First aquatic life, then plant life, tree life, then insect life, then bird's life, then beast life, then human life, then civilized human life. So this is the process of evolution. Now, we are supposed to be civilized human being. This life is especially meant for how to get out of this evolutionary process. How to get out of this evolutionary process. The evolutionary process means transmigration of the soul from one body to another. We do not wish to die, but we have to accept death. This is our conditional stage of life.