Therefore, when they are bound together, the will to receive is negated by the light within, and a created being is unable to achieve a final form until the light has been removed from it at least once. For after the light is removed from it, the will to receive begins to yearn very much for the light, and this yearning determines and finalizes the appropriate form that the will to receive will take. Subsequently, when the light returns and is enclothed in the form that the will to receive has taken, from that point the entity is categorized as possessing two separate elements: vessel and light, or body and vitality. Consider this carefully, as it is the most profound of ideas.
When the Will to Receive Is Saturated with Light
Petichah LeChokhmat HaKabbalah 4:2