The root of Adam HaRishon is dust that is unfit for sowing, as it is written, “And the Lord God formed the man from dust of the earth.” This means that were it not for the correction of the Adama [earth], which is Bina, Adom [red], it would be unfit to receive the abundance.
This is considered that Adam HaRishon was born circumcised. Because of the sin of the tree of knowledge, he was pulled at his foreskin, as it is written, “From dust you are and unto dust you shall return.” By retrieving the foreskin to himself, which is the vessels of reception for himself, the will to receive became rooted in the generations following him.
This is why Abraham went on the right, the correction of the quality of Hesed [mercy], meaning that he wants Hassadim [pl. of Hesed]. For this reason, from the quality of Hassadim, he extends Dvekut [adhesion] with the Life of Lives.
However, Isaac went on the left line, called Gevura, to work in Hitgabrut [overcoming] the vessels of reception so as to work in order to bestow.
And because he was working on the left, to see his situation within reason, he sees the faults and the state of separation, since in the state of the left, a person is in a state of deficiency while the Creator is called “whole,” and “The cursed does not cling to the Blessed.”
For this reason, Isaac had to be included with Abraham. This is why it was written, “Abraham begot Isaac.” Although everyone knows this, but it teaches us that in the quality of Isaac, who is “left,” there is also the quality of “right,” which is Hesed, and from there it receives life. Jacob is the middle line, so he certainly contains Hassadim.
However, David, whose quality is Malchut, Messiah—on which there were the Tzimtzum [restriction] and concealment—cannot receive any light on her own quality. Instead, she must receive from Zeir Anpin, her husband, which means that she was built from Malchut of Zeir Anpin, regarded as “the vacant space.” Hence, she received from them, meaning from Abraham, Jacob, and Joseph, who are above Malchut. Therefore, she received illumination from them.