Krishna says to Arjuna:
Many, many births both you and I have passed. I can remember all of them, but you cannot. (Bhagavad-gita 4.5)
We cannot even remember all that happens in this one lifetime. We forget, because we are changing our bodies. A grown man cannot remember what he said or how he acted on the lap of his mother, because his body has changed. We say we are growing, but actually we are changing bodies. This is explained in Bhagavad-gita (2.13):
As the embodied soul continually passes in this body from boyhood to youth to old age, the soul similarly passes into another body at death.
We are bewildered, because we accept different types of bodies. When a man is sleeping, his gross body is lying in bed, but he accepts a subtle body in his dream and completely forgets his gross body. Although sleeping, he dreams that he is awake, and he acts with the body that he has concocted in his dream. Material existence is like that. Constitutionally, we are pure spirit souls, and we have nothing to do with material bodies, but under the spell of maya (illusion), we have accepted bodies for sense gratification, and we act in so many ways, forgetting our real identity. As a man lies in bed dreaming, we are lying in the lap of material nature, forgetting our real self.
The difference between God and the minute living entity is that God does not change His body; therefore He never forgets. Whereas our bodies are changing at every moment, and therefore we are full of ignorance. Krishna does not change; therefore, He is full of knowledge. He says in Bhagavad-gita (7.26):
I know everything that has happened in the past, everything that is happening now, and all things that are yet to be. I also know all living entities, but Me no one knows.
Death exists only for the body.
For the soul there is never birth nor death. Nor, once having been, does he ever cease to be. That which pervades the entire body is indestructible. No one is able to destroy the imperishable soul. ( Bhagavad-gita 2.20)
Is there life after death?
The Soul Lives Forever
Krishna says in Bhagavad-gita (2.12):
Never was there a time when I did not exist, nor you, nor all these kings; nor in the future shall any of us cease to be.
Both God and the living entities are individuals. They existed in the past; they exist now, and both God and the living entities will exist as individuals in the future.
The Body is Always Dead
The living being is not a creation of matter. The living being is the force who brings the material world into being, in the same way that the architect or engineer is the living force who brings the ingredients together to construct a building, and the tailor is the living force who puts cloth together to make a shirt or pair of pants. The living force brings the material body into existence. The material body is not the living being; but the living being is within this body, spreading its influence all over the body through the medium of consciousness. Consciousness is the symptom of the presence of the soul.
Spirit and matter are categorically two different substances. One is conscious, whereas the other is not. Matter has no consciousness; it is inert, and it is therefore called the inferior energy of the Lord. Matter has no power to take shape independently, no more than a building has the power to take shape independently. An engineer brings the ingredients together and gives them shape. Similarly, the body, which is a combination of inert elements such as earth, water, fire and air, does not take shape automatically. It is the living force, or soul (jivatma), that combines the material ingredients and gives them shape according to the soul’s desires.
Transmigration of the Soul
The soul develops different kinds of bodies. There are 8,400,000 species of life or different kinds of bodies. There are different styles of clothing in the department store, and we purchase a suit of clothing according to our capacity to pay for it. If we have a good capacity, we shall buy a good suit. If not, we’ll have to go to the Salvation Army or thrift shop and purchase used clothing. Similarly, there are high-grade and low-grade bodies. The human body marks the high point of the soul’s evolution, or transmigration, through the lower species of life.
The body is described in the Bhagavad-gita as a dress of the eternal spirit soul. There it is said:
As a person puts on new garments, giving up the old ones, similarly the soul accepts new material bodies, giving up the old and useless ones.
This is called samsara, the cycle of birth and death.
dehino ‘smin yatha dehe
kaumaram yauvanam jara
As the embodied soul continually passes in this body from boyhood to youth to old age, the soul similarly passes into another body at death. The self-realized soul is not bewildered by such a change. (Bhagavad-gita 2.13)