The upper Light is eternal and constant. Rest is a consequence of His creation that He wanted to create. Thus, everything that is not the Light represents a garment that is put one on top of another and covers the Light that is inside of them.
Each covering, from first to last, is called the desire to receive, except for the internal Light that is the desire to bestow, the Creator.
This is why we are talking about multiple stages, worlds, Partzufim, Sefirot, and so on, although all of them are only the garments of the Light. Each cover is like a screen that simply receives a certain type of impression from the Light, within which it’s possible to differentiate between things that come directly from the properties of the Light and things that are originated by the coverings.
So, the same thing can be explained from the side of desires,vessels, and from the side of the Light: relative to an action and an intention. The Light at the zero phase (Shoresh de Shoresh) decided to create something that is opposite to it, something that would want to receive from it, enjoy it, and consume it. It is called the creation, the act of birth.
Everything that evolves in this world originates from the authentic impulse that is the desire of the Light in correlation with the desire to receive, that is, the desire to create something that would take advantage of the Light and be delighted by it. The Creator has built in such a desire in the very root of the creation, to create in order to bestow good.
This instinct is in the depths of our desires, otherwise we would not be able to have children and care for them. Although in the end, it is distorted by our selfish desires and takes a completely different egoistic form.
The so-called four phases of the Direct Light are the garments on the upper Light, which develop from it by the chain of cause and effect and thus conceal it more and more. If the Light decided to create and created something opposite to it, then now this opposition develops more and more: starting with the zero stage, where everything was permitted, and to stage four, which prohibited all egoistic pleasure.
From the 3rd part of the Daily Kabbalah Lesson 6/26/12, Talmud Eser Sefirot