Any garment should end with four tassels that symbolize four qualities of desire: Hochma, Bina, Zeir Anpin, and Malchut. The ends of the tassels necessarily must be tied in a knot, which means restriction.
This means that you to some extent restrict each of the desires and then you can use them, already directed at bestowal. You can’t do anything with an unrestricted desire. It must end somewhere, have a restriction, a screen, and a Reflected Light.
For example, a glass has its own shape. Similarly, the desire has its shape if you restrict it by the knots. The four tassels should be not only on garments, but also on the blanket that we use during the day’s sleep, because in this case, it is considered a garment. Therefore, it is necessary to tie knots on the four corners of the blanket.
According to the Torah, there are our basic internal property, then the soul, body, garment, and then the external world. A garment is the external desires, which can be gradually attracted and corrected so that they relate to you like your body. We study this in the writings of the Ari.
Spiritual laws work only for correction of the more internal and the more external desires, and are built on various restrictions, so that it would be possible to gradually work off all the desires and fill the corrected soul with the Upper Light.
From KabTV’s “Secrets of the Eternal Book” 9/28/16