Durga represents the Divine Mother. She is the energy aspect of the Lord. Without Durga, Shiva has no expression and without Shiva, Durga has no existence. Shiva is the soul of Durga; Durga is identical with Shiva. Lord Shiva is only the silent witness. He is motionless, absolutely changeless. He is not affected by the cosmic play. It is Durga who does everything. Shakti is the omnipotent power of the Lord, or the Cosmic Energy.