ואמרת אליו בהעלתך את הנרות (בהעלותך ח:ב)

The Tzemach Tzedek of Lubavitch related a story:

The Ba’al Shem Tov was supposed to have a learning session with a group of talmidim. However, only one candle was available to light the room. The talmidim were distraught about sitting in darkness, and they knew that the Ba’al Shem Tov preferred it when there was ample light in the room when they studied together.

When the Ba’al Shem Tov entered the dimly lit room, he turned to his Talmidim and said: “Yidden, the room needs light! My main Avodah (service) to Hashem is to bring light to the Yidden. Why is there only one lit candle?”.

The Ba’al Shem Tov was unhappy with the lack of light since he was committed to bringing light to the Yidden. He instructed the talmidim to remove the “icicles” hanging from the gutters, which appeared as wax candles, and light them.  The talmidim, following their Rebbe’s instructions, lit the “icicles” and witnessed as these “icicle candles” shone forth with their otherworldly light.