The oneness of the Brahman is not in opposition to the multiplicity of the manifestation which is still the Brahman, the “one without a second”. We however also cannot get caught up in trying to define or limit the Brahman to any particular form or formulation of existence. Therefore, we see the vedantic formulation “neti, neti” not this, not that, to remind us that we cannot capture Brahman in human thought or word.
There is no opposition between the One and the Many in this formulation of an omnipresent reality.
Man’s importance in this scheme of things is to act as the point at which Brahman can become self-conscious of its evolutionary life expressions in material forms and thought. “To fulfill God in life is man’s manhood.” “A divine existence is his objective.”
reference: Sri Aurobindo, The Life Divine, Chapter 5, The Destiny of the Individual