Answer: Spiritual desire is the ten Sefirot: nine Sefirot ending with Malchut.
The upper light, which spreads through the four phases of direct light, forms nine Sefirot: Keter, Hochma, Bina, and Zeir Anpin, which in turn consists of six Sefirot. Passing through them, the light builds the fifth stage—Malchut.
The first nine properties are the properties of bestowal, and Malchut is the property of reception.
When Malchut becomes like the nine Sefirot, a conjugation occurs with it and the properties of bestowal. Therefore, it can receive the upper light, but only if it has a screen (reduction) to receive the upper light.
Thus, their connection arises on the conjugation of Malchut with the nine Sefirot.
At the same time, all nine Sefirot begin to shine. The word “Sefira” comes from the word “shine.”
Question: Does Malchut’s demand makes them shine?
Answer: Yes. Malchut itself does nothing; it is an absolutely black body.
Question: How do properties differ from desires — the nine Sefirot from Malchut?
Answer: The nine Sefirot are the properties of light, and Malchut is desire.
Direct light spreads through four stages and builds Malchut, and Malchut begins to comprehend them. All interactions occur between the stages of direct light and Malchut, as between the Creator and creation.
From the Kabbalah Lesson in Russian 11/25/18