yatha sarva-gatam sauksmyad
akasam nopalipyate
sarvatravasthito dehe
tathatma nopalipyate

"The sky, due to its subtle nature, does not mix with anything, although it is all-pervading. Similarly, the soul situated in Brahman vision does not mix with the body, though situated in that body."

Sri Krishna cites an example. Space is spread everywhere. But is it influenced by any? Space is in air, water and in the sky. Space is in our body. But space in an object is not affected by the object. Space in water is never wet! Space in an elephant does not behave like an elephant! Thus space -akash- is never influenced by the object in which it is there! Why it is so? Because of the imperceptible nature -sookshmam - of space. If a thread carries the scent of the flower, which is tied with, it is because thread is perceptible. It has a surface area on which flower is able to pass on its scent. Space has no dimensions and so no surface, and can never be perceived! Therefore, no other object can influence on space any characteristic. On the same analogy, atman is also imperceptible and so can never be influenced by the body in which atman is resident, in spite of infinite time of association. Yatha = just as, sarva-ghatam = every where present, akasam = space, sauksmyat = being imperceptible or atomic, nopalipyate = is not affected or influenced [by the objects in which space exists], tatha = similarly, sarvatra = in every, vastitho = object, deha = of bodies, atma = soul or atman, nopalipyate = is not influenced [by the body's nature]. Atman is inside body; but body's nature has no effect on the atman or soul. Because atman is imperceptible, like space. We can perceive and understand atman only by shastras. Amrutam is atman as it is never destroyable. Sri Thayar presents one amrutam - our atman - to another Amrutam - the Lord - as fruits of our devotion.