The Chhandogya Upanishad : 2.1 : the tripod of Indian Culture, being constituted of the Upanishads, the Brahmasutras and the Bhagavadgita.
13/12/2018 The Chhandogya Upanishad : Chapter One: Vaishvanara-Vidya -2 2.THE COURSE OF THE SOUL AFTER DEATH (CONTINUED)-1. These souls which are to return to the mortal world get identified in a subtle manner by their subtle bodies through these natural phenomena, viz., space, air, cloud, rain and foodstuff, even up to the grains like sesamum and barley, beans, rice and wheat, herbs, plants and trees, etc. It is very difficult to understand how they get mixed up with these things. In a very subtle form, these souls are supposed to get identified with these natural things. And they get into the body of the individual through the foodstuff with which they have been identified. Then the same process of birth takes place. The individual soul has come from the above, after finishing its career of enjoyment due to the performance of good deeds here. The soul gets identified in every manner, in every way characteristically, with the particular level through which it has to pass