The Preparation Is Our Avodah
It is told that the Yismach Yisroel did not allow chassidim into his room during candle lighting on Chanuka. One chassid, however, refused to be dissuaded. His desire to see the Rebbe light the candles was so strong that he hid in one of the closets and peered out through a crack in the door.
He watched the Rebbe's face as he prepared before lighting the menora. It shone and burned like a torch suffused with an otherworldly light as he made his hachanos (preparations).
Then, just as the Rebbe was about to perform the mitzva and kindle the wicks, he set aside this passionate burning and clothed himself in a demure, reserved manner as he lit the menora. The chassid thought this strange indeed. Before the mitzva, while involved in the hachanos, the Rebbe had burned with passionate fire for Hashem, yet during the mitzva itself he seemed calm, collected and reserved. Of course, the chassid could say nothing and ask nothing, for that would reveal that he had secretly stolen into the room and seen what he was forbidden to see.
The next day, the Rebbe approached the chassid and remarked to him, with no introduction, "The awakening that a man has while doing the mitzva comes from On High and not from himself or his efforts down here below. Ober vus der mentsch ken un vus der mentsch darf (but what a person can achieve, he must do): that is the awakening with which he must awaken himself while he prepares in advance to do the mitzva. This requires him to awaken his heart to love and awe of Hashem. This excitement and enthusiasm will then ignite his heart and set it aflame in dveikus with his Creator."
This, of course, was the answer to the chassid's secret question.