Bhagavad Gita 2.28अव्यक्तादीनि भूतानि व्यक्तमध्यानि भारत।अव्यक्तनिधनान्येव तत्र का परिदेवना ॥

The physical body is a combination of the five elements. It is seen by the physical eyes only after the five elements have entered into such combination. After death, the body disintegrates and the five elements go back to their source it cannot be seen. Therefore, the body can be seen only in the middle state. The relationship as son, friend, teacher, father, mother, wife, brother and sister is formed through the body on account of attachment and Moha (delusion). Just as planks unite and separate in a river, just as pilgrims unite and separate in a public inn, so also fathers, mothers, sons and brothers unite and separate in this world. This world is a very big public inn. People unite and separate.There is no pot in the beginning and in the end. Even if you see the pot in the middle, you should think and feel that it is illusory and does not really exist. So also there is no body in the beginning and in the end. That which does not exist in the beginning and in the end must be illusory in the middle also. You must think and feel that the body does not really exist in the middle as well.He who thus understands the nature of the body and all human relationships based on it, will not grieve.