All souls root in one creature, one soul of Adam HaRishon. All of the events unfold in it. The soul was divided into multiple parts upon introduction of the will to receive into it, which is opposed to unity. The breaking is necessary for correction, and otherwise, it was impossible to break the soul into pieces.
Following the example of the king who transferred his treasure overseas by handing a coin to each of his couriers to assure success of the delivery, the soul of Adam HaRishon also gets corrected (transitions from the corporeal world into the spiritual one) part by part.
Breaking into parts is regarded as a “sin” although in truth, nobody sinned. In fact, a force aimed at receiving entered the collective soul in order to saturate each of its parts and separate it from the others. From that moment onward, each soul’s work lies in overcoming this force and reattaching its part of the common treasure to the unified interconnection.
In relation to me, all other parts are complete, and their seemingly broken and corrupted state is the effect of my own flaw. This is how a person should view the world, not fantasizing but inwardly working on himself. In that case, his outlook will change, and he will see that the surrounding world is filled with perfection and only he is corrupted.
Thereby, a person gets to know the initial breaking of the unified soul. By correcting himself, he returns to its parts as Adam, meaning that he acquires the collective intention toward all parts, all “transgressions,” and toward the entire force of detachment that penetrated the system and cracked it into 600 000 souls.
The correction is performed from light to heavy, according to the unfolding of the Aviut (coarseness, thickness) of the given part or, in other words, according to resentment it feels toward the others. After all, no matter how high a person ascends, the evil inclination rules over him anyway. However, a person is always given the exact measure he is able to correct. We need to realize free will by way of unifying with the group.
From the 1st part of the Daily Kabbalah Lesson 11/2/10, “Which Degree Should One Achieve so He Will Not Have to Reincarnate?”