All souls are equal, connected to each other as equal branches stemming from one root.
All Israelites are therefore called real brothers by virtue of the source of their souls in the One God.
Like the children of one father, like branches that come from one root, so all the souls of Israel are the outgrowth of one inclusive soul–the "Congregation of Israel," Knesset Israel.
Knesset Israel is to be found deep within each individual, where there exists only one shared "soul," a soul that is not intrinsically divided but only seems that way, just as a ray refracted by polished glass splits into thousands of flickering lights of various colors.
At their source, there is no difference between great and small, between one color and another.
–Rabbi Adin Steinsaltz
From Understanding the Tanya, Chapter 32, Rabbi Adin Steinsaltz