Brahman is the name given to the fundamental Reality behind and beyond everything. It is the Origin and Source of Creation, its stable unchanging basis. It is also within each and every element of creation, from the smallest atom to the universes drifting in Space. It is within you and me and every creature. It is also beyond Creation and eludes every kind of description. The word comes from the root brh which means IT is ever expanding, ever manifesting or very simply there is no beginning and no end to Brahman. It is the Infinite and the Eternal Truth of things. It brings out all that is within itself through Its Shakti as a writer writes a cosmic poem or a painter paints what is within it. The writer is in his poem, in all its events and characters since each is something of Himself projected in Time and Space. He is also independent of all that He creates as a poet exists independent of his writings as well. Hence Brahman cannot be defined but known by experience. One can know Brahman in its essence through Yoga.
Nirguna and Saguna are two aspects of the same Brahman just as when a man sitting silently thinking nothing is the same man when he gets up and moves and writes and acts thereby bringing out all that was within him. So too Nirguna is Brahman inative, passive, silent, featureless, formless whereas Saguna is the same Brahman with infinite qualities that assume countless names and forms and yet cannot be exhausted by any or all of them. Nirguna is when qualities are held back as in a person who is in deep sleep. Saguna is when the person is awake conscious of a personality, impulse to act and create.
When the Nirguna Brahman is seized from within by His own Shakti, Power that was at rest in Him, to create then creation begins. It is the Shakti of Brahman, His bride if you like who creates and whatever She creates, Brahman is there as the silent Witness and Presence since the two are always One in all the many worlds.
Hope this answers your question.
Affectionately,
Alok Da
