The concealment of the divine light (or “countenance”) is an essential quality of the world in which both soul and body exist.
It is the backdrop, the space that allows for their existence.
The concept of a “world” (the world of Atzilut or Beria, etc.) is similar to that of a “field” (in the scientific sense) in which a certain law, a certain level of concealment of the countenance, exists.
Accordingly, the concept of “world” describes a group of entities that share a common level of divine concealment and are therefore regarded as sharing the same plane of existence.
In this sense, the degree of divine concealment in this world equally affects all the creations within it, and the distinctions between them are themselves a part of the nature of the world and the divine concealment.
Rabbi Adin Steinsaltz