Translation and commentary by Eliyahu Munk from Shnei Luchot HaBrit Something that has been separated by G‑d should not be fused again by man…

Parashat Kedoshim addresses the legislation dealing with forbidden sexual relations. The scriptural commentary by Rekanati, regarding the verse:

"None of you shall come near anyone of his own flesh to uncover nakedness, I am G‑d" (Lev.18:6)

states that most kabbalists do not offer a specific reason for this commandment; some of them claim that the reason is that something that has been separated by G‑d should not be fused again by man. The branch is not to be made part of the trunk. Since each generation is further removed from the original pair of human beings, it would be wrong, if, through incestual relationships, we were to reverse this process.

Relatives are like branches of a tree (root) which extend further and further. We must not make new "trees" through these forbidden unions. These branches are to receive their growth-sustaining moisture from other branches, not from their own root. The original root is perceived as if it was already drying up. Sexual union with the forbidden categories of relatives contributes to further drying out of the vital juices of the parties concerned. The metaphor is applied to the drying up of our affinity to the celestial Chariot, the supernal carriers of G‑d's Presence. Acts performed in our world are liable to have a damaging effect on the equilibrium in the Celestial Regions…

Cain was not forbidden to marry his sister, seeing his sister was one of the original seven human beings who had been created or born under the direct influence of Heavenly forces, corresponding to the seven days of Creation. [The seven are Adam, Eve, Cain, his twin-sister, and Abel and his two twin-sisters. Ed.]

Some other reasons for the laws against forbidden relations are advanced by some of the more recent commentators. They say that there are ten emanations by means of which G‑d established a physical world. He remained close to these emanations, exerting His influence on them, remaining inseparable from them. We also know that acts performed in our world are liable to have a damaging effect on the equilibrium in the Celestial Regions. If someone has sexual relations with one of the forbidden categories of relatives, he is looked upon as having taken hold of the scepter of the Celestial King in an unauthorized manner, since in those regions a close relationship between "brothers" is commonplace. [The word "staff" could be a euphemism for the male organ. Ed.]

These commentators describe intercourse with one's mother as disturbing the equilibrium in the domain of the sefira of bina, also known as the "Mother of Children". It also disturbs the equilibrium of the Shechina, also known as the "Mother of All". This is the reason that the Torah writes "You should not reveal your mother's nakedness, for she is your mother" (Lev.18:7) twice in succession. The only one who is entitled to exert his influence [masculinity] upon the domain of the sefira of bina is the King of Kings. Anyone who usurps this privilege [vicariously of course, Ed.] is guilty of the death penalty.