“Death is imposed on the individual life both by the conditions of its own existence and by its relations to the All-Force which mainfests itself in the universe.” Death is essentially the dissolution of an individual formation in the process of Time. Without this action, the world would be stagnant and essentially unable to evolve and change as all the manifested forms would have virtually unending persistence and remain stuck in the limitations that they bring with them. “For the individual life is a particular play of energy specialised to constitute, maintain, energise and finally to dissolve when its utility is over, one of the myriad forms which all serve, each in its own place, time and scope, the whole play of the universe.”
We find in the Taittiriya Upanishad a discussion of how Matter is “food” and that the eater, eating, is eaten, showing the interconnectedness and relation of each to all in this give and take of the life force energy.
After growing and striving to exist and thrive in a world where there is intense competition for resources, eventually the individual form reaches a point where it has either been damaged in the proces, or at the very least has reached the end of the particular capabilities of the particular form. At that point, the death of the body opens up new opportunities for the soul to escape the limitations and move to the next stage of the evolutionary process in a newly formed body.
The soul seeks its experience and maturity in an exclusive concentration in a material form, but eventually, the soul needs to be able to move on and gain new experience in new forms and in new ways. The soul’s journey through successive lives involves a process of death and rebirth many times over. This describes the law and necessity of the process of Death as an integral part of the process of Life. “death is necessary because eternal change of form is the sole immortality to which the finite living substance can aspire and eternal change of experience the sole infinity to which the finite mind involved in living body can attain.”
reference: Sri Aurobindo, The Life Divine, Chapter 20, Death, Desire and Incapacity