The work of the sons of Israel in Egypt is the work on unification in the ten. However, this unification is impossible in Egypt; therefore, they flee from there. After all, they wanted to unite in the desire to enjoy. All the problems in Egypt are the realization that we are unable to unite, no matter how hard we try.
Thus, seven years of satiation and seven years of famine pass in our unsuccessful attempts. However, each time we gain increasingly subtle and sublime definitions and eventually come to the need for exiting Egypt. Moses understands that it is necessary to separate from Pharaoh; he goes to Pharaoh and demands the people be let go.
But previously there was no such awareness and it was unclear that the desire to enjoy completely dominates a person. Even now it seems to us that it is enough to make an effort and we will unite. So we try again and again and 400 years pass in these attempts, that is, in all four stages.
There can be no unification in Egypt; after all, we are in our egoism! And even if we reach some kind of unity, then at the next degree we discover that it was egoistic and not for the sake of bestowal, the way it seemed to us.
The years of exile are degrees. If we are in 250th year of exile, it means that we managed to unite at the 250th degree. But suddenly the left line is revealed showing me that there is no unity and I hate everyone. It means that now, at the 251st degree I discovered a much greater desire to enjoy than before. So we climb up the degrees, stepping with the left foot and then with the right one.
There is unity in Egypt, but it is egoistic. After all, all of Egypt is arranged for us to understand that we will not have life in egoism.
From the 1st part of the Daily Kabbalah Lesson 3/9/18, Writings of Rabash, The Rungs of the Ladder, “What Are the Two Discernments Before Lishma“