Midrash sa Genesis 30:14: Ein Yaakov (Glick Edition), Aggadat Bereshit, Bereshit Rabbah & Sifrei Bamidbar

Our Rabbis were taught: (Num. 15, 30) "But the person that doth aught with a high hand; this refers to Menasseh b. Hezekiah who sat and lectured on topics with the object of fault-finding," saying, "Could not Moses have found something better than (Gen. 36, 22) "And Lotan's sister was Thimna, or, (Ib.) she was a concubine of Eliphaz b. Esau," or that of (Ib. 13, 14) "And Reuben went in the days of the wheat harvest and found mandrakes in the field." A heavenly voice was then heard saying (Ps. 50, 20) "Thou sittest and speakest against thy brother, against thy own mother's sons thou utterest slander, etc." And to him also applies the words of tradition: (Is. 5, 18) Wee unto those that draw iniquity with the cords of falsehood, and as with a wagon-rope, sinfulnesses." What does a wagon-rope mean? A. Assi said: "In the beginning, the evil inclination appears as thin as the thread of a spider's web; and finally he becomes as thick as a wagon rope." Since we have already arrived at it, let us see what does And Lotan's sister was Thimna really mean. Thimna was a princess, as it is written (Gen. 36, 40) Duke Thimna, and dukedom means a kingdom without a crown. She desired to become a proselyte, but Abraham, Isaac, and Jacob did not accept her. And she went and became the concubine of Eliphaz b. Esau, saying it is better to be a servant in this nation than to be a princess of another. And her offspring was Amalek, who troubled Israel as a punishment to their parents, who ought not to have driven her away.

[3] Another interpretation: And she vowed a vow, and said, "If you will see me, then you will see that I am barren, and Zion is barren, as it is said, "Sing, O barren one" (Isaiah 54:1). If you see me, then you will also see Zion, and remember me, for me, and do not forget your truth, for Zion. There are seven barren ones corresponding to the seven days of creation. The first is Sarah, as it is written, "And Sarai was barren" (Genesis 11:30), corresponding to the first day. And what was created on the first day? Heaven and Earth, which belong to this purchase by the Holy One, blessed be He, as it is said, "Blessed is Avram to G-d on High, Possessor of heaven and earth" [Rashi: having acquired them by creating them] (Genesis 14:19). The second is Rebecca, as it is said, "And Isaac entreated the Lord for his wife, because she was barren" (Genesis 25:21), corresponding to the second day. And what was created on the second day? The firmament, as it is said, "Let there be a firmament in the midst of the waters, and let it separate between water and water" (Genesis 1:6). Rebecca also gave birth to two sons, Jacob and Esau, as it is said, "And I will separate you from the peoples" (Leviticus 20:26). The third is Leah, as it is said, "And the Lord saw that Leah was hated, and He opened her womb" (Genesis 29:31), corresponding to the third day. And what was created on the third day? Vegetation, as it is said, "Let the earth sprout vegetation" (Genesis 1:11). And Reuben, the son of Leah, built, as it is said, "And Reuben went in the days of the wheat harvest" (Genesis 30:14). The fourth is Rachel, corresponding to the fourth day. And what was created on the fourth day? The sun, moon, stars, and constellations, as it is said, "And God said, 'Let there be lights'" (Genesis 1:14). And Joseph, the son of Rachel, stood as her offspring, and they bowed down to him, as it is said, "And behold, the sun, the moon, and eleven stars were bowing down to me" (Genesis 37:9). The fifth corresponds to Thursday, and what was created on Thursday? Birds that fly in the air (Genesis 1:20). And so was Samuel, the son of Hannah, like a bird flying from place to place and from country to country, and eventually returning to his nest. And so was Samuel involved in the affairs of Israel, going to all places, as it is said, "And he used to go yearly on circuit to Bethel and Gilgal and Mizpah, and he judged Israel in all these places" And his return was to Ramah, for there was his home. (1 Samuel 7:16-17) The sixth corresponds to the Hazzelelponith, the mother of Samson, as it is written: "And their sister (Hazzelelponith) [Hazzelelponi]"(1 Chronicles 4:3) . What was created on the sixth day? Man, and what happened to man? He died by the hand of his wife, as it is written: "And to Adam He said... for from the tree... you shall surely die" (Genesis 3:17), and Samson, too, died at the hands of his wife, as it is written: "And he loved a woman in the valley of Sorek, and her name was Delilah" (Judges 16:4). The Philistines seized him and gouged out his eyes (Judges 16:21). The seventh corresponds to Zion, as it is written: "And on the seventh day He rested" (Exodus 20:11). And Zion is my resting place forever (Psalm 132:14). Therefore, Isaiah said: "Sing, O barren one, you who did not bear" (Isaiah 54:1).

“Reuben went during the days of wheat harvest, found mandrakes in the field, and brought them to Leah, his mother. Rachel said to Leah: Please give me from your son’s mandrakes” (Genesis 30:14).
“Reuben went during the days of wheat harvest.” “Train the lad in accordance with his way; even when he grows old, he will not turn from it” (Proverbs 22:6). “May this land be given to your servants…” (Numbers 32:5).
“The sated were hired for bread, but the hungry have ceased; while the barren has borne seven, the one with many children is miserable” (I Samuel 2:5). “The sated were hired [niskaru] for bread” – this is Leah, who was sated with sons and was rewarded [niskara]. “But the hungry have ceased [ḥadelu]” – this is Rachel, who was hungry for children but was stymied [ḥadela]. “While the barren [akara] has borne seven” – this is Leah, who was the primary one [ikara] in the household, and bore seven. “The one with many children is miserable” – this is Rachel, who was worthy to have the majority of the children emerge from her, and was miserable. Who did this? It is: “The Lord puts to death and brings to life” (I Samuel 2:6).