Thus, the whole difference between the higher worlds and this world is that as long as the will to receive that is subsumed in His shefa has not materialized into its final form, it is still found in the spiritual worlds, which are loftier than this world, whereas once the will to receive has materialized into its final form, it is regarded as being found in this world.
The aforementioned devolvement in which the will to receive is brought into its final form in this world follows the order of the four levels that correspond to the four letters of the four-letter name of God (the Tetragrammaton). For the four letters of the Tetragrammaton, yod-heh-vav-heh, encompass all of reality without excluding even the most minute particle.