Kabbalah zu Jechezkiel 46:1

Also one should be careful to only have relations with this wife from Shabbat to Shabbat, and on Rosh Chodesh and Yom Tovs, since there is no unification of ‘Tzadik’ above except for those times, as it says “Thus said Hashem: The gate of the inner court that faces the east shall be shut the six working days; but on the Shabbat day it shall be opened, and in the day of the new moon it shall be opened” (Ezekiel 46:1). Similarly it says in the Zohar in Noach: 362. Because the six days are the non-holy mundane days, and the gate should be shut so that the ordinary does not make use of the sacred. “But on the Shabbat day it shall be opened, and on the day of the new moon it shall be opened,” because at those times, the sacred makes use of the sacred, and the moon, WHICH IS THE FEMALE PRINCIPLE, shines in order to unite with the sun, WHICH IS ZEIR ANPIN.