The Zohar: When darkness comes and Malchut connects to it, she governs and shines in Hochma, which is her governance. And since she lacks the Light of Hassadim, all her openings are blocked from all sides, for all the Lights freeze within her and there is no vent in her, through which any Light can appear.
She is filled with Light, but the vents are blocked. Afterwards, when the middle line awakens in her and opens the vents, they will receive the illumination of Hochma from her, which was blocked within her at that time. It is written that they crave to permeate the Nukva precisely when she is discerned as small ways and blocked vents, since only then is the Hochma in her complete.
The night is actually full of Light, but we are unable to see in the night since we lack the Light of love and bestowal (Hassadim) to see the Light. Only in the Light of Hassadim can we compel the Light of Hochma to reveal itself and to shine in the Light of Hassadim. The greater the Light of Hassadim, the greater the revelation.
Night or darkness is a state where I am in an ocean of the Light of Hochma, but I have no Light of Hassadim. If I begin developing inner qualities of love and bestowal (the Light of Hassadim), then the Light of Hochma begins to shine for me little by little. This means that I awaken dawn, the Light of morning, and then the day.
From noon and further on, the Light of Hassadim, my force of bestowal, weakens and I begin descending from the level of Hassadim that I once had. It is as if dusk, a lessening of the Light of Hochma in the Light of Hassadim, sets in. That is when evening comes, followed by night. Stated differently, my desire to enjoy has grown and it leaves no strength for me to remain in bestowal and love (Hassadim); it gains more and more power over me. The dark forces of night seize me and I give up, descending into the darkness and becoming incapable of love and bestowal.
But then, while in this dark, I again accumulate the strength to give, and starting from midnight, I begin combining Hochma and Hassadim, so that one Light shines within the other. This is how I reveal the Light.
All of this is done by a person if he overcomes his desire to enjoy through his aspiration for bestowal; then he sees the Light. And vice-versa, he sees darkness to the degree that his egoism overcomes him. That is how we advance through our spiritual development, from day to night, again and again. Everything depends on the person alone, since on the part of the Creator, the Light permanently surrounds us, as it is written, “I did not change My HaVaYaH,” and, “The law is given and one cannot break it.” Everything is already given to you, and from now on you are welcome to do whatever you want.