There are two discernments of Shabbat: 1) of Beresheet (Genesis/beginning); 2) of the six thousand years. And the difference between them is this: It is known that there is a stop, and there is rest. A stop is where there is nothing more to add. A rest, however, stems from the words “standing” and “resting,” meaning that one is in the middle of one’s work. And since one has no strength to continue with one’s work, he stands and rests to revive himself, and afterwards continues with his work.
A Shabbat of Beresheet is a discernment of having nothing more to add. This is called “a stop.” A Shabbat of the six thousand years is considered rest, by which one receives strength to continue one’s work on the weekdays.
Now we can understand the words of our sages: “Shabbat said, ‘You have given everyone a mate, but to me You did not.’” And the Creator replied, “Israel will be your partner.” A partner means ZA. If there is a Nukva, there can be a Zivug (coupling), and from the Zivug come the offspring, meaning renewal and additions.
Nukva is a deficiency. If there is a deficiency in some place, there is room to correct the deficiency, and all the corrections are considered having been fulfilled by extending the Upper Light in the place of the lack. It follows that there was no deficiency here to begin with, but all the lack that they previously considered to be a deficiency, came in the form of correction to begin with, meaning that thus the Upper Light would flow from Above.
This is similar to one who delves in some matter, and exerts to understand it. And when he attains the meaning, then it is to the contrary, he does not feel that he was previously suffering when he did not understand the matter. Rather, he is glad because now he has joy. The joy is measured by the extent of the effort that he made prior to understanding the matter.
Thus, the delving time is called Nukva, a deficiency. And when one unites with the deficiency, he produces the offspring, the renewal. This is what the Shabbat argued, “Since there is no work on Shabbat, there will be no offspring and renewals.”