There is nothing but the soul, the one “round” desire to receive, that is full of Light. The Light begins to operate inside; it spurs the desire and “warms it up,” puts it out of balance, and is revealed to it gradually. Throughout the process, the Lights and the vessels influence one another and descend from Ein Sof (Infinity).
Let’s take a system, any system, mechanical, electrical, or hydraulic. If it receives an electric shock, it is put out of balance in “one blow,” and begins to gradually quiet down until it returns to the previous balanced state.
This is what happened with Malchut of Ein Sof: the system received a “blow” when it discovered the contrast between the Light and the vessel, the horrible gap between the infinite minus (vessel) and the infinite plus (Light). This nightmare is terrible for the desire, and it cannot bear and digest this. Therefore it restricted itself and moved on to the next chain of actions. The desire won’t calm down until it performs them. After the decision that has been taken in Ein Sof, all the other decisions come automatically, all the way from top down, until our world.
Now our work begins; the work of ascending back to Ein Sof. The way back totally matches the descent that preceded it: We go through the same stages, but in an opposite order and according to our will, as we request the correction (MAN) first. This is the whole difference.
From the 4th part of the Daily Kabbalah Lesson 2/12/12, “Introduction to the Study of the Ten Sefirot”