What Need of Man has God?

Once I asked my teacher, Kalman the cabalist, the following question:  For what purpose did God create man?  I understand that man needs God.  But what need of man has God?  My teacher closed his eyes and a thousand wounds, petrified arteries traveled by terror-stricken truths, drew a tangled labyrinth on his forehead.  After a few minutes of contemplation, his lips formed a delicate, very distant smile.  "The Holy Books teach us," he said, "that if man were conscious of his power, he would lose his faith or his reason.  For man carries within him a role which transcends him.  God needs him to be ONE.  The Messiah, called to liberate man, can only be liberated by him.  We know that not only man and the universe will be freed, but also the one who established their laws and their relations.  It follows that man - who is nothing but a handful of earth - is capable of reuniting time and its source, and of giving back to God his own image." - Elie Wiesel