The sefer Amudeha Shiva by Rabbi Betzalel ben Shlomo of Kobrin brings a wonderful insight. The Midrash (Yalkut Shimoni, Mishlei 964) address the Pasuk וְ רָ ח ֹק מִ פּ ְ נִ ינִ ים מִ כְ רָ הּ – And far beyond pearls is her worth. What is "her worth"? It is her pregnancy. The explanation is, Chazal tell us, know that this child in Sarah's womb is a pearl! The Midrash continues and says: דָּרְ שׁ ָה צֶמֶר וּפִשְׁתִּים – She sought wool and flax; namely, a separation between Yitzchak and Yishmael, as she told Avraham to drive them away.
These ideas are difficult to understand, says the sefer Amudeha Shiva. What is the connection and explanation of her pregnancy and how is it compared to pearls, and what is the connection between wool and flax to Yitzchak and Yishmael? Furthermore, it says "she rewarded him with good," but surely, she would not reward him with evil! He explains that the Arizal wrote that Yishmael was from the root of Kayin and Yitzchak was from the root of Hevel. Hevel was initially meant to be bound in holiness, but he gazed at the Shechinah and was killed. Yitzchak merited in his place and was bound at the age of 37, the numerical value of הבל. The yesod of these matters is brought in the words of the Arizal (Likutei Torah). Adam and Hevel sinned with sight – as they gazed – and they were reincarnated in both Avraham and Yitzchak; with Yitzchak rectifying Hevel and Avraham rectifying Adam. This is why it says אֶת־שֶׁם־בְּנוֹ הַנּוֹלַד־לוֹ – the name of his son born to him, when we already knew this name. After he was born he was not referred to as הַנּוֹלַד־לוֹ except to hint that he is his son, born to him previously, and now once more – because Avraham was Adam, and Yitzchak was Hevel, his son.
ל' ו ֹ בְּ ' נוֹ הַ ' נּוֹלַד are the initials of הבל. This was rectified through the Akeida; therefore, Yitzchak was not bound until he was 37 years old, the numerical value of Hevel. This is also why Avraham says: לֹהִים יִרְאֶה־לּוֹ הַשֶּׂה לְעֹלָה בְּנִי -אֱ – meaning, to rectify the sin of Hevel who sinned with sight, as הַ ' שּׂ ֶ ה לְ ' עֹלָה בְּ ' נִ י is also the initials of Hevel. וַיֵלְכוּ שְׁנֵיהֶם יַחְדָּו – they went both of them together for one purpose; one to rectify Adam and the other to rectify Hevel.
What exactly happened at Akeidat Yitzchak? Yitzchak was bound with his head back and his eyes upward – at that moment he nourished his eyes from the Shechinah, since Hakadosh Baruch Hu opened the heavens to show the angels how a father binds his only son at His command. The Midrash says (Bereishit Rabbah, 65:10): וַיְהִי כִּי זָקֵן יִצְחָק וַתִּכְהֶיןָ עֵינָיו – And it came to pass when Yitzchak was old and his eyes were dim from seeing, from the power of that sight; that when Avraham bound his son on the altar, the ministering angels wept and tears fell from their eyes into his eyes, and they were imprinted in his eyes, and when he aged, his eyes dimmed. Another explanation given is that he lifted his eyes to the heavens and gazed at the Shechinah. Hakadosh Baruch Hu said, if I kill him now, I will be condemning Avraham; rather, I decree that his eyes dim, and when he aged, his eyes dimmed.
Thus, Hevel's sin was not rectified; Hevel gazed at the Shechinah and died. Yitzchak came to rectify him, but ultimately, he too gazed at the Shechinah – and who finally rectified them? Chazal say it was Moshe Rabbeinu! The Arizal continues and says, Moshe, a gilgul of Hevel, did not want to repeat the same sin from his first incarnation, and therefore hid his face: וַיַּסְתֵּר מֹשֶׁה פָּנָיו כִּי יָרֵא מֵהַבִּיט אֶל־הָאֱלֹהִים. In this, he rectified the blemish of Hevel.
We can now understand why Adam HaRishon was commanded not to eat from the Eitz HaDa’at – the Tree of Knowledge. It is because it was mixed with good and evil, and the moment Adam and Chava ate from it, good and evil became mixed within them. As a result, Chava conceived two children – one good, Hevel, and one evil, Kayin. When good and evil are mixed together, the evil came and killed the good, leaving only the evil of Kayin behind. Therefore, Shet had to be brought into the world by Adam and Chava, and it was within Shet that the soul of Hevel was conceived, as it is written: לֹהִים זֶרַע אַחֵר תַּחַת הֶבֶל כִּי הֲרָגוֹ קָיִן-כִּי שׁ ָת לִי אֱ – For G-d has appointed me another seed instead of Hevel, for Kayin killed him.
Sarah Imenu came and what did she do? דָּרְ שׁ ָה צֶמֶר וּפִשְׁתִּים – she said to Avraham: “Look at what came from mixing good with evil! If you want a child who is entirely good, there must not be another mixture – Yitzchak is the wool and Yishmael is the linen – do not combine them together!” Therefore, she suggested he take Hagar, her maidservant. The mefarshim say, she specifically suggested Hagar, her Egyptian maidservant, because that way Yishmael could come from her, and the linen could be kept separate from the wool. Sarah Imeini rewarded him with good in that the wool – and good – came exclusively from her.
If so, all the waste (psolet) went to Yishmael. How old was Yishmael when Yitzchak Avinu was born? Thirteen. The question arises – why didn’t Avraham send Yishmael away before the age of thirteen? Why wait until he was thirteen?
