Our reality is divided into worlds, Partzufim, and Sefirot, which are the wrapping and place where the soul is found. The soul is the outcome of the evolution of this structure and it develops from its inner point.
Similarly, the still nature developed first in our world and then the nature of the vegetative on this planet, then the animals and finally man. This is exactly how the spiritual system that preceded the system of nature developed.
There is a correlation between the systems of the worlds and all its mechanisms and the system of the soul that is in the system of the worlds. The worlds are only the exterior part while the soul is internal.
There is in fact only one soul, but we don’t feel it. We will have to attain it in the future. The more we connect, the more we become part of this system, the more we begin to feel it. But in the meantime we are disconnected from this feeling.
The system of the worlds is divided into internality and externality. The internality is the systems of the world of Ein Sof (Infinity) and the world of AK and Atzilut. The externality is the worlds of BYA, including this world, which is the lowest level.
There is a soul that undergoes the shattering in these worlds, and it also includes two parts: internality and externality, both before and after the shattering, both for the sake of corruption and correction.
The internality of the souls are the people who yearn straight to the Creator, (Yashar-El), who yearn for adhesion with Him. 5,774 years ago Adam was the first to discover this yearning and discovered the system of the general soul and the worlds.
Then there were twenty generations until Abraham gathered the people who wanted to attain the Creator into a group and called it Israel (Yashar-El). Thus he also distinguished them from all the others so that they would be able to start working according to the principle of “love thy friend as thyself” and attain the equivalence of form with the Creator, and accordingly attain the upper system.
Later this group underwent the shattering and was exiled; as of today, this group, together with all those who join it day by day, is formatting and preparing itself for the correction. In general, the phase of correction has come not only for this group but for all of humanity.
On the whole, the division into two parts is kept the whole way: the nation of Israel (that yearns for the Creator) is divided into two parts, GE (internality) and AHP (externality). Humanity is also divided into internality and externality, and on the whole we can identify the two parts in every individual, since the “the individual and the general are equal.” This refers both to the worlds and to the souls after the general soul was shattered.
The internality and the externality are opposite from one another and the Upper Light operates on them in order to coordinate between the system of the worlds and the system of the souls.
The influence of the Upper Light on us is also divided into internality and externality because if there is a division in the vessels into two parts with respect to the Light, the Creator, the upper system; the separation of functions is discernable in every facet.
Accordingly, the externality of the worlds is called the nations of the world and the internality is called Israel, according to the direction of Yashar-El. The nation of Israel and the nations of the world are also divided into internality and externality.
Every world, every Partzuf, in the general system in which the souls exist until they connect into one soul; this whole operating system that manages the souls is also divided into internality and externality, into GE (vessels of bestowal) and AHP (vessels of receiving).
From the Daily Kabbalah Lesson 3/3/14, Writings of Baal HaSulam