We cannot perceive the spiritual world because we do not have adequate properties like it. For example, there are radio waves around us that we do not see and feel, but we create instruments that let us sense them.
Likewise, we need to build a device that will sense the spiritual world. It is called the soul and it must have the properties of the upper world, bestowal and mutual connection, which are absolutely opposite to our world.
We can find them in a group, in strict adherence to what the wisdom of Kabbalah teaches. As you accumulate sensory and rational material, you will begin to feel how it gradually forms in you. You will learn more about all sorts of patterns of spiritual elements, their various compounds, classes, levels, and so on.
In other words, when studying the science of Kabbalah—the physics of the upper world—certain feelings, properties, and sensations gradually form in you. You will build models inside yourself: “This is Bina, this is Malchut, this is Zeir Anpin, it is above the Parsa, this is below the Parsa,” and so on. This is the gradual design of your soul.
From the Kabbalah Lesson in Russian 12/23/18