Just as a man casts off worn-out clothes and puts on new ones, so also the embodied Self casts off worn-out bodies and enters others which are new.
In simple words
Krishna gives Arjuna a vivid picture: "Think of how you take off old worn-out clothes and put on fresh new ones. That is exactly what the soul does — it sheds a worn-out body and moves into a new one."
This interpretation draws on a specific tradition and may not represent the view of any single school. For authoritative guidance within a specific tradition, seek a qualified teacher.
BG 2.22
This is one of the many celebrated verses frequently cited from the Gita, wherein through a most practical illustration, it is made clear how the individual soul, abandoning one body, identifies itself with another body and thereby acquires new experiences in new circumstances. The illustration employed by Vyasa is exceedingly well-known.
Just as a person in practical life dons appropriate garments suited to different occasions, so too does the individual soul, casting off one body, assumes another body in order to gain experiences of a different nature. No one goes to his office wearing night clothes, nor does he play tennis in office attire. He wears garments suited to the occasion and the activity. The same principle applies to death.
This illustration is so simple and intelligible that through it, not only Arjuna, but any student or listener of the Gita, even after a long passage of time, can clearly understand the matter of the abandonment of the body. Changing worn-out garments causes no suffering to anyone, and especially when old clothes are discarded and new ones are donned, there is no cause for distress whatsoever. Similarly, when the individual soul finds that its present body no longer serves any purpose for it, it casts off that worn-out body. Only the one who dwells in the body can determine its worn-out condition, for this worn-out state is related neither to the age of the one who inhabits it nor to his physical condition.
Many critics oppose this verse, failing to understand the significance of the word "worn-out." Their principal argument is that in the world, many children and young people are seen to die, whose bodies were not worn-out. Though this statement may be correct from a physical standpoint, when viewed from the perspective of the soul's development, if the body has become useless for the soul's evolution, then that body must be considered worn-out. A wealthy person may wish to change his house or vehicle every year, and each time he finds a buyer. From the wealthy person's perspective, that house or vehicle has become old or useless; but from the buyer's perspective, that same house is as useful as a new one. Similarly, only the individual soul dwelling in the body can determine whether the body is worn-out or not.
This verse establishes the principle of rebirth, which we have already discussed in the 12th verse.
Through this illustration, Arjuna must surely have understood that death frightens only those who lack knowledge of it. But the person who understands the mystery and significance of death experiences neither pain nor sorrow—just as the body experiences no distress from changing garments, nor do we remain forever unclothed after discarding one garment. Similarly, from the perspective of development, the soul too abandons the body and assumes a new, suitable body to gain fresh experiences. There is no suffering in this. This development and change is for the soul, not for the eternal, conscious Self. The Self is ever complete; it has no need for development.
Why is the Self unchanging and immutable? The Blessed Lord says—