The further the Partzufim descend, growing more distant from the perfection of the world of Infinity, the more they divide. The difference between the right and left sides, the upper and lower parts, the front and back, the male and female parts, becomes clearer and more significant.
When there is perfection, everyone is perfect in their actions, although of course, each one in his own way. When there is perfection, all are equal. If we attain the total inter-inclusion of souls, then even the tiniest soul attains all the other souls and there is no difference between them. Each one attains the entire Light of Infinity, but in his own way, which is precisely his virtue.
Therefore, the lower spiritual objects descend, the more complex they appear, consisting of different parts. At first all of these parts were in the world of Infinity, and overall it seemed as if there were no differences between them. Then they started to become slightly different: one was a little more to the right and the other to the left (from the point of view of the Light of Hassadim), or above versus below (from the point of view of the Light of Hochma), or in the front versus in the back (from the point of view of the Kelim).
All sorts of differentiating forms appeared, indicating a lack of perfection, which needs to be made up for. In the world of Atzilut these qualities become very noticeable: In Atik it is impossible to detect any differences, in Arich Anpin they are already a little bit apparent, and in Aba ve Ima the divisions are very clear – the front and back sides, above and below (Aba ve Ima and YESHSUT).
However, ZON are already two different Partzufim: Zeir Anpin and Nukva, which require greater corrections in order to complete each other. We, the souls, are completely divided from one another by horrible hatred, repulsion, and a huge abyss between us. There is no more discussion of complementing each other in any way. We must first realize our evil and understand how divided and distant we are, then desire to come closer, and then find a means for it and the One who can help us.
We broke and lost consciousness. All we can do is ask for help, if we can. That is why there is a ladder of worlds, which are degrees of discerning the flaws and separation between all of their components.
And there is a reverse law operating here. If we look from above downward, then the difference between the male and female parts (Zahar and Nekeva), the Creator and creation, bestowal and reception, becomes revealed more and more. But when ascending back up, we reveal this difference more and more, first considering ourselves totally righteous, and then discovering an increasingly greater difference between ourselves and bestowal until we reveal all of it. Thus, we end up with two opposite triangles.
When we ascend, then we reveal an increasingly greater number of details in the worlds, which the Light illuminates for us. The upper level in relation to the lower is like the entire world next to a tiny grain of sand according to the number of constituent parts and their quality.
From the 3rd part of the Daily Kabbalah Lesson 1/9/11, Talmud Eser Sefirot