The entire content of this mail is an abstract from Swami Adidevananda's translation of The Gita Bhashya, published by Ramakrishna Mission.
The materialistic standpoint - 26-28
Jatasya hi dhruva mrutyuh dhruvam janma mrutasya cha I
Tasmad apari harye arthe na tvam shochitum arhasi II sloka 27
जातस्य हि ध्रुवः मृत्युः ध्रुवं जन्म मृतस्य च ।
तस्मात अपरी हार्ये अर्थे न त्वं शोचितुम अर्हसि ।।श्लोक २७
For death is certain for the born and rebirth is certain for the dead; T
herefore y
ou should not feel grief for what is inevitable
For what has originated, the destruction is certain - it is seen to be inevitable. Similarly what has perished will inevitably originate. How should this be understood - that there is origination for that (entity) which has perished? It is seen that an existing entity only can originate and not a non-existent one. Origination, annihilation etc. are merely particular states of an existent entity.
Lets take an example - thread does really exist. When arranged in a particular way, it is called clothes. it is seen that even those who call the cloth a new entity, will admit that no entity over and above the particular arrangement of threads is seen. It is therefore not tenable to believe that a new entity has emerged, since the process of manufacture has only created a new name and special functions for the thread. No new entity emerges.
Origination & annihilation
Sri Krishna syas that not even the slightest grief arising from seeing an entity passing existing stage to an opposite stage, is justifiable in regard to human beings, etc.