A college student once asked the Rebbe what is his job. The Rebbe gestured to the ceiling of his room and replied:
Do you see that light bulb? It is connected by wires to an electrical generating station that powers the whole of Brooklyn. And that plant is connected to turbo-generators at Niagara Falls that power the whole of New York State and more.
Every one of us is a light bulb wired into an infinitely powerful generator. But the room may still be dark, because the connection has yet to be made, and it is hard to find a switch in the dark.
The job of a rebbe is to take your hand in that dark room and help it find the switch.