You must understand how this gradual process develops and advances stage by stage in accordance with the dichotomy of body and soul, for it is quite evident that the body, being thick and coarse, can only be produced through concealment and a lack of light. Thus, as long as the lights were shining with great power, the root of the body was not discernible among them. This is why in AV, where the lights are very dominant, there is no mention of any letter, for no root of the vessel can be seen or discerned there. At first it is revealed, albeit slightly, in the Ear. More of it is revealed in the Nose and even more in the Mouth, until it is completely revealed.