21. Atman is indestructible, eternal, unborn and undecaying. Hence you cannot kill or induce another to be killed. A dreamer cannot kill the waker’s mind. Clay cannot be destroyed by breaking clay pots. A product cannot destroy the producer. Only ignorance causes this misconception.
All grief stems from wrong identification and irrational concepts. We relate unintelligently to objects and beings in the world. They have a birth and death, a beginning and an end. How can you expect to have them with you forever? Even when you have them your mind changes. That which gave you happiness earlier now gives pain.
Atman is indestructible. Various names and forms are projected upon Atman. They come and go. They are born and they die. Atman is there forever.
22. In this verse Krsna defines birth and death. The movement of the subtle body, mind and intellect, and causal body, vasanas, from one gross body to another is called the death of the former body and birth of the latter. Atman cannot move as it is all-pervading. Movement is possible only from a place where a thing exists to a place where it does not exist. Since Atman is present everywhere It cannot move.
The sun above is one. Wherever there is a reflecting medium a reflected sun appears. The reflected sun acquires the traits of the reflecting medium and loses the original qualities of the sun. When the mirror moves from one frame to another it is called the death of the former and birth of the latter reflected sun. While this change is taking place the sun above remains immaculate, neither dead nor born.
Similarly reflected beings are created wherever there is a mind, intellect and vasanas. This combine moves from one gross body to another. Atman above is untouched by these changes. That Atman is you. You are not the individual body that comes into being temporarily only to die away.
In this verse Krsna gives the example of clothes. Just as a person discards worn-out clothes to adorn new clothes the inner personality abandons a jaded body for a new body. This example fits perfectly. The person decides when and how often to change clothes. Similarly the mind and intellect decide the change, not external circumstances. In other words, every death is self-designed. A wealthy person changes clothes several times a day. A poor person may change once in a few days. So also, one rich with desires changes bodies often. One with fewer desires does not need such frequent changes. A person lives so long as his desires are being fulfilled. When it is no longer possible to fulfil his desires and there is a mismatch between the desires and the environment, death takes place. The person then moves on to another body and environment that are more conducive for fulfilment of his desires. Hence death is a blessing, not something to be mourned. Only ignorance and attachment make us suffer.
Just as the individual gives life to the clothes, the subtle body, mind and intellect, energise the physical body. The mind and intellect need the body to fulfil desires just as a person needs clothes to go out into the world. Even within a lifetime the physical body changes according to the mind. When the mind wants to be fit the body becomes healthy. The surroundings also get modified when the mind changes. When the mind is conscious of cleanliness the environment becomes neat and tidy.
In fact, even during your life it is desire that decides your movement from one place to another.