Zohar 3:100b

Jewish Mysticism
R. Eleazar said- It is written, “on the full moon for our feast day” (Ps. 81-4) . . . [ba-keseh] with [the letter] he, for the moon is concealed (de-itkasseya’ sihara). . . . Come and see- On that day the moon is hidden, and she does not shine until the tenth of the month when Israel all repent in a perfect repentance, and the supernal mother returns and illuminates her. On that day she takes the illumination of the mother, and joy is found in everything. Thus it is written, yom ha-kippurim hu (“This is the day of Yom Kippur”) (Lev. 23-27). It should have been yom kippur [in the singular]. Why is it yom ha-kippurim [in the plural]? To indicate that two lights are illumined as one, the upper radiance shining upon the lower radiance. On that day she shines from the supernal light and not from the light of the sun. Therefore it is written “on the full moon for our feast day.” R. Abba sent [a question] to R. Simeon- What is the [appropriate] time for the copulation of the Community of Israel and the holy king? He responded to him [with the words of Abraham]- “And besides, she is in truth my sister, my father’s daughter though not my mother’s daughter; and she became my wife” (Gen. 20-12). . . . R. Hiyya said to R. Abba- What did he say in his response to you? He said that the coupling of the king and the queen is certainly only at the time that she is illumined from the supernal father, for when she is illumined from him they call her “holy” (kodesh), for she takes from the house of the father, and they are united as one, for the king is called “holy,” as it is written, “Israel is holy unto the Lord” (Jer. 2-3), for he takes from the place that is called “holy.” Consequently, “she is my father’s daughter though not my mother’s daughter,” for this name [kodesh] is from the house of the father and not from the house of the mother. And thus “she became my wife,” to unite as one at that time and not another time, at the time she takes from the house of the father and not at the time she takes from the house of the mother. The day of Yom Kippur proves the point for sexual intercourse is forbidden, for the coupling does not take place since she takes from the house of the mother rather than from the house of the father.

Translated by Elliot Wolfson in “Fore/giveness on the Way- Nesting in the Womb of Response,” Graven Images- Studies in Culture, Law, and the Sacred 4 (1998)- 153-169.