The Zohar, Chapter “Miketz (At the End),” Item 33: “Them that await His mercy.” “Them that await His mercy” are those who engage in Torah at night and partake with Divinity. And when the morning comes, they await His mercy.
The Zohar also talks about this in the article, “The Night of the Bride.” It describes all the days of exile as a dark night, during which we prepare our desires (Kelim) for the connection between the Groom and the Bride that will happen in the morning.
All who prepare for this meeting are called the dwellers of the King’s palace. The moment that they complete building the wedding canopy (Huppah, symbolizing a screen and the Reflected Light), the Creator (Zeir Anpin) unites with His Shechina, which is the union of all souls. This is the vessel for receiving the Light. Then the Bride unites with the Groom; the two compliment each other and attain a state of perfection and peace.
When a person engages in Torah at night, a thread of mercy extends upon him during the day….
It is impossible to engage in the Torah during the day, because the day is when unification happens. At that point, everything is revealed and there is no more work to be done. Our work lies in exercising our freedom of choice, while in fact we already exist in the perfect state. We just need to “prefer” it, meaning to choose day over night.
When we decide that bestowal is day, we will reveal it as being day. Through the Reflected Light, we awaken day and Light instead of darkness. This is why all the work happens at night; it’s because all our choice and efforts are concentrated there. There is no work that can be done during the “day.”