זוהר בראשית — דף קנו ע”ב

Everything in this world depends on a supernal appointee above. On the verses about the mandrakes, the Zohar explains that it was not the mandrakes that gave Rachel a child: the Holy One, blessed be He, steered events so that Issachar would be born, who holds to the Torah more than all the tribes, and the mandrakes sent up the fragrance of Torah before Him. The word “he” points to the hidden upper world, from which the Torah comes, the tree of life, to which Issachar is attached. But Rachel was remembered by the Holy One, blessed be He, and not by the mandrakes: “God heard her and opened her womb,” for children depend on destiny. Leah went out to meet Jacob out of humility, with Rachel’s permission, and spoke to him outside and not in the house, so as not to hurt her sister.