The Eternal Self indeed is God. The Self is the only One that remains in the past, present and future. The identity of the God is eternal, immutable, immortal, and infinitive.
Before the evolution of the universe the INFINITIVE darkness was pervading which was devoid of any substance. God, the Eternal Primordial in the darkness became "I" in its Ego, Thought in its Pervasiveness, Sound in its Speed, Fire, the Great Causal Sphere.
Evolution of the Universe
The sparks of this ever increasing causal fire became sub-particles. These sub-particles began to scatter and spread rapidly. When their speed abated, they adhered together on account of their inherent nature. They became stars, planets, water, earth and the universe with their characteristic movements and gravitational force.
They evolved into all life forms that grew, moved, walked and ran and became feelings and finer sensations. They became pain and pleasure on account of experiences. By deeper inquiry these experiences gave birth to various religions and science of critical reasoning. These finally became the Knowledge of very Self which is nothing but the realization that Universe is the evolution of very Self.