The jivatma does not get destroyed with the death of the body. It takes re-birth. Knowing this, we wonder what the logic behind performing the shraddha (pronounced as shraadh) ritual is. When we make all the offerings, where do they go and how do they reach the person who is possibly in his/her next birth?
Bhagavadpad Sri Adi Shankaracharyaji has written a detailed commentary on the Chhandogya Upanishad which deals with this subject. Pujyapad Puri Shankaracharyaji gives an example of a bank to explain this to us. If a person has enough money in his bank, he does not need anyone else to deposit more in order to live his life comfortably. Those persons who have done enough good deeds and thus, earned enough punya in their life, can function very well without any son or grandson do shraddha for them. However, those who have less balance of good deeds, and pass away, then via the ritual of shraddha they obtain punya. The mantras, proper method and all the material that is offered reaches the jivatma that has passed on. The last rites, shraddha, and Tarpana, performed as prescribed in shastras, generate the punya required by that jiva on the basis of the relationship of the person performing the ritual, the vow undertaken, the feeling and actual performance of the ritual.
The Matysa Puran has details on shraddha as well. If we live in Bharat and want to send money to America, we can do this by converting currency. Similarly, what is offered in shraddha reaches the body the jiva has taken in appropriate form that would nourish it. If the ancestor has become a preta the food suitable to it will reach, similarly if he has become a tiger, then food appropriate for a tiger will reach.
When the asthis (leftover bones and ashes post cremation) of the departed are immersed in the Ganga or Triveni, then the punya gained will influence the bhava rajya of the jivatma. To understand “bhava rajya” we can visualise that if someone becomes a tiger in his dream, then after some time becomes a king, then a Gandharva, then a human, and so on. This change in the bhava rajya created changes in the type of bodies, hence. If the jivatma has not taken birth as yet, then, the punya through the rituals creates changes in this bhava rajya giving the jiva a divine body. Such is the principle.
Hence, we must perform all the rites and rituals when our family members depart, and it is essential for us to offer shraddha. The shraddha ritual is also a way to free ourselves of the debt of our ancestors.
Read this fascinating real story related to shraddha ritual.