The relation of the Kshara Purusha and the Akshara Purusha is described by Sri Aurobindo through a comparison with the elements of the natural world. The power of wind moves and pervades the element of ether. Similarly, the Kshara Purusha, manifest, mobile and active pervades the Akshara Purusha, unmanifest, unmoving and inactive. These are not two separate and independent beings, but two aspects of one being, with the motion taking place against the unmoving background that is always there but not always perceptible by us because our view is oriented outwards and distracted by the motion, action and forms of the manifested world.
“The Kshara spirit visible to us as all natural existence and the totality of all existences moves and acts pervadingly in the immobile and eternal Akshara. This mobile Power of Self acts in that fundamental stability of Self….”
The Akshara “…in its highest status… is an unmanifest beyond even the unmanifest principle of the original cosmic Prakriti, Avyakta, and, if the soul turns to this Immutable, the hold of cosmos and Nature falls away from it and it passes beyond birth to an unchanging eternal existence.”
“These two then are the two spirits we see in the world; one emerges in front in its action, the other remains behind it steadfast in that perpetual silence from which the action comes and in which all actions cease and disappear into timeless being, Nirvana.”
Sri Aurobindo, Essays on the Gita, Second Series, Part II, Chapter 15, The Three Purushas, pg. 423