Brahman was Alone

In the beginning, there was no differentiation and the Brahman was alone. But the differentiation has led to illusion. Men desire wives, wealth and other objects. As long as one of these objects is not obtained, men feel themselves to be incomplete. But completeness only comes from identifying one's mind with the Brahman. A wife is like speech; a son is like the breath of life ; the eyes and the ears are like wealth. But all of this must be attained if man is to be complete. A person who attains this wisdom becomes satiated.
"Upanishads"