Baal HaSulam, “Introduction to the Study of the Ten Sefirot,” Item 134: You should know this law, that there is disclosure only in a place where there was concealment. This is similar to matters of this world where the absence precedes the existence, since the growth of wheat appears only where it was sown and rotted.
It is the same with higher matters, where concealment and disclosure relate to each other as the wick to the light that catches it. This is because any concealment, once it is corrected, is a reason for disclosure of the Light related to that kind of concealment, and the Light that appears clings to it like flame to a wick. Remember this on all your ways.
The oil itself cannot burn. In order to light it, we need a wick. The wick represents the opposite property, on one hand, and on the other hand, the connection between the Light, the fire that needs air and oil to burn.
The wick connects the oil, the fuel, and the air. The wick itself is meaningless. It can be made of some material that is not consumed. It is only the link that connects the oil, which we need to light, and the air that is necessary for combustion. If there is a connection between Malchut and Bina, the fuel and the air, then in the gap between their attributes there can be fire, the Light.
From the 1st part of the Daily Kabbalah Lesson 1/3/13, “The Introduction to the Study of the Ten Sefirot”