Answer: It’s our egoism. In the world in which we exist, there is an “I,” the most important persona. Why? Because that’s how I experience myself. I am the most important, the most central, the most.
Our initial nature was intentionally created as the opposite of the Creator, so that as we begin to experience qualities of bestowal coming from Him, we can compare these qualities with our own egoistic qualities and begin to construct our understanding of the difference between this and that.
It is similar to the way we build an electrical system with various resistors, condensers, batteries, and other components. The elements may be opposite to one another, but thanks to the interaction between them, they create a correctly functioning system.
In our world too, everything is built on action and reaction because we, as created beings, can experience any property, sensation, or quality only with respect to its opposite: from darkness to light, from sour to sweet, and so on. There is no other way for us to discern anything. Two qualities need to be present in us, and we feel the difference between them.
The Creator has only one quality, the quality of bestowal, which is His initial state. He only created the quality of reception in order for us to exist and to be able to develop the quality of bestowal above it. It turns out that we exist in our world strictly in the movement from egoism to altruism. And this difference between them needs to remain.
Several interesting conclusions can be drawn from this. First, egoism is not destroyed, because otherwise we will lose the sensation of altruism. We cannot remove the quality of hatred, because without it we would not be able to experience love. We cannot get rid of sinners, thieves, and bullies, otherwise we will cease to experience what it means to be righteous. Everything is attained through contrast. That’s why it turns out that everything has to be in the world, but only in correct balance.
This is what the Kabbalist strives for because he understands how all of nature is constructed. He is not planning on destroying anyone or correcting anyone; he only demonstrates what exists in front of you, but what you do with it is your choice. In other words, this is a very generous methodology, relying on well-balanced individuals.
From Kabbalah lesson in Russian 4/2/17