Baal HaSulam, “600,000 Souls”: It is said that there are 600,000 souls, and each soul divides into several sparks. We must understand how it is possible for the spiritual to divide, since initially, only one soul was created, the soul of Adam ha Rishon. In my opinion, there is indeed only one soul in the world, as it is written (Genesis, 2:7), “and breathed into his nostrils the breath of life.” The same soul exists in all the children of Israel, complete in each and every one, as in Adam ha Rishon, since the spiritual is indivisible and cannot be cut—which is rather a trait of corporeal things. Yet, saying that there are 600,000 souls and sparks of souls appears as though it is divided by the force of the egoism of each person.
The Creator created only this one soul of Adam ha Rishon. But because of the force of shattering, which has entered us, each of us senses only himself. However, by virtue of actions called “the Torah and commandments,” a person has an opportunity to attract upon himself the Light from the common soul, if he wants to draw closer to it.
The soul is a collection of all souls merged into a single whole. The more a person aspires towards it by the means of the group, the friends, and the study, the greater is the illumination that he invokes from there. This illumination helps him to remove the partition that fences him off this soul and to reveal it.
That is, everyone discovers that they are inside this soul. But all parts, into which, as it seems to us, we are now divided by imagining different people, they differ from one another and stem from different roots. Some relate to 600,000 souls, and others to the sparks. But this determines only the differences on the path: who comes first, who at the end, and who in the middle in the process of correction; who belongs to the degrees of HBT–HGT–NHY, “fathers,” “sons,” or the entire world. And ultimately, everybody discovers the common soul in its entire fullness, without any difference between us.
From the 1st part of the Daily Kabbalah Lesson 8/26/2012, “600,000 Souls”