Kabbalists know that they can’t get to a desired change and cross the barrier between this world and the spiritual world on their own. Just like a football player knows that he won’t play alone on the field, even if he is the most talented player in the world. An even better example is dancing. When two people are dancing one might be up while the other is down, and the situation changes within a matter of seconds. And the dance goes on as long as the situations keep changing. All the dancers know that they are dependent on each other.
Courtesy of http://www.youtube.com/watch?v=aN4TD-G0BKg