The Zohar, "Introduction of The Zohar," Chapter "BeLaila de Kala (On the Night of the Bride)”: …through the deficiency of the light, which is the night—which includes all the Dinim and torments, which are opposite to the quality of day, Hesed—there is fear of Him. Were it not for the fear, the measure of day and morning would not appear.
Our first correction is fear. I am afraid of receiving the Light directly into my desire. I am cautious; I tremble and fear that I won’t be able to hold back and will "open the door" to the pleasures that come through in the Light.
Like a guest who refuses a feast, I lock all the locks, fearing the possibility of receiving these pleasures not for the sake of bestowal.
The first phase of correcting my desire is to keep it back from directly receiving the Light. This is called "return from fear."
This is the first quality that I have to acquire, the fear that all of my actions would be only for the sake of bestowal.
From the 1st part of the Daily Kabbalah Lesson 11/16/10, The Zohar
Where’s The Pleasure?