Zohar Shelach Lecha
(The beginning of this discussion is missing in the original Zohar text)
Rabbi Shimon praises his son Rabbi Elazar for sharing his study about Jacob and Rachel. He adds that God forbids to think that even though Rachel was barren at that time, Jacob was wise. If he didn’t know that Leah is his wife, he wouldn’t bury her in the Cave of the Machpelah. By doing so, he continued a complete unification with Leah after passing from this world. If Jacob didn’t know and accept Leah as his wife, he would have buried her outside the cave. He brought Leah into the Cave of the Machpelah, and Rachel was buried outside. When Jacob died, he was buried next to Leah to keep the unification with her.
Leah has the aspect of the upper H of the name, which is Binah. Rachel is Malchut, the aspect of the lower H, and that is why she was buried outside. Leah was spiritually higher. When the Final Redemption comes, Rachel will welcome Mashiach and unite with Jacob, Tiferet, and an aspect of Zeir Anpin, to unify the upper and lower Lights in Malchut.
Adam knew that the Cave of the Machpelah is proper for his resting place. Eve died first and was buried in the Cave. When Adam died, he was buried next to Eve to be one with her.
Sarah died and was buried in the Cave. When Eve saw her, she rose and welcomed her with joy. Sarah was buried at a distance that is no more than two cubits from Eve. Abraham died and was buried next to Sarah. Rebecca died and was buried in the Cave. Sarah saw her, rose, and welcomed her. Isaac died and was buried next to Rebecca to be one with her. Leah died and was buried in the Cave. Rebecca saw her, rose, and welcomed her. Jacob died and was buried next to her as one. After Jacob was buried in the Cave, all became as one, males and females together.