159. Therefore, it was this grade, NAMELY THE "TENT DOOR," WHICH IS MALCHUT, that informed Abraham OF YITZCHAK'S BIRTH, as we have explained the words, "And he said, I will certainly return to you at this season..." Although it reads, "And he said," it does not say who said. So this is the "tent door," BECAUSE "AND HE SAID" REFERS TO THE SHECHINAH. And Sarah heard this grade, WHICH IS THE "TENT DOOR," from which she had heard nothing before, AS IT WAS SPEAKING WITH ABRAHAM, as it is written, "And Sarah heard it THE WORDS OF the tent door," which declared "I will certainly return to you at this season, and, lo, Sarah your wife shall have a son."
160. Come and behold, the love of the Holy One, blessed be He, for Abraham is so great that Isaac was not born until after Abraham was circumcised. And only after he was circumcised was he informed of Isaac, because only then was the seed holy; before he was circumcised, the seed was not holy. And then it became as it is written, "Wherein is its seed after its kind" (Beresheet 1:12), WHICH REFERS TO A KIND AS HOLY AS ABRAHAM.
161. Come and behold, before Abraham was circumcised, his seed was not holy because it passed through the foreskin and clung to the lower foreskin. But after he was circumcised, his seed issued in holiness and it clung to the holiness of above, and he begot up above. Thus, Abraham clung to his grade, WHICH IS CHESED, properly. Come and behold, when Abraham begot Isaac, he was born holy, as should properly be. So these waters, WHICH ALLUDE TO ABRAHAM WHO IS CHESED, conceived and bore darkness. IN OTHER WORDS, ISAAC, WHO IS THE SECRET OF THE LEFT COLUMN, WAS DARKNESS, BEFORE HE WAS CLOTHED WITH THE CHASSADIM OF ABRAHAM. AFTER HE ISSUED FROM ABRAHAM, HE WAS CLOTHED BY HIS CHASSADIM AND BECAME 'LIGHT.'
162. One day, Rabbi Elazar asks his father, Rabbi Shimon, Why did the Holy One, blessed be He, name him Isaac before he was born, as it is written, "and you shall call his name Isaac?" (Beresheet 17:19). AND WE SHOULD NOT SAY IT WAS BECAUSE SHE SAID "ELOHIM HAS MADE LAUGHTER (HEB. TZECHOK) FOR ME..." (BERESHEET 21:6). Because even before he came into the world, the Holy One, blessed be He, called him Isaac, BEFORE REASON WAS GIVEN FOR IT.
163. He replies, But we have learned that fire, WHICH IS THE LEFT ASPECT AND GVURAH, received water, WHICH IS THE RIGHT ASPECT AND CHESED, as water came from the aspect of Gvurah. THIS MEANS THAT THE LEFT AND RIGHT WERE COMBINED AND BECAME INCLUDED IN EACH OTHER. THUS, THE LEFT ASPECT BECAME THE ASPECT OF THE WINE THAT GLADDENS ELOHIM AND MAN. And it is required of the Levites, WHO ARE DRAWN FROM THE LEFT COLUMN, that they bring happiness to that side, NAMELY THE LEFT SIDE, with musical instruments and praising songs that correspond to that side. THIS MEANS THAT MUSICAL INSTRUMENTS AND PRAISING SONGS ARE ALSO DRAWN FROM THE LEFT SIDE. And this is why Isaac means laughter and enjoyment; he came from that side, THE LEFT SIDE, and clung to it.
164. Come and behold, Isaac himself is pleasure and laughter because he exchanged water for fire, and fire for water. THUS, THE LEFT AND RIGHT ARE INCLUDED IN EACH OTHER - BECAUSE ISAAC IS THE ASPECT OF THE LEFT, WHICH IS THE FIRE THAT BECAME INCLUDED WITHIN THE WATER, WHICH IS CHESED AND THE RIGHT ASPECT. THIS CAUSES ALL DELIGHT AND HAPPINESS TO BE DRAWN FROM THE LEFT SIDE. This is why the Holy One, blessed be He, named him ISAAC (LIT. 'HE WILL LAUGH') even before be came into the world, and announced it to Abraham.
165. Come and behold, the Holy One, blessed be He, allowed all children, EXCEPT ISAAC, to be named by their parents. Even women named their children. But here the Holy One, blessed be He, did not allow Yitzchak's mother to name him - only Abraham. As it is written, "And you shall call his name Isaac" (Beresheet 17:19)" - you and no one else, in order to exchange water with fire, and fire with water, WHICH REFERS TO THE INCLUSION OF THE LEFT WITH THE RIGHT AND THE RIGHT WITH THE LEFT, so that Isaac may be included within his side, THE RIGHT SIDE.