מדרש אויף בראשית 36:1

And these are the generations of Aaron and Moses on the day that God spoke to Moses on Mount Sinai (Numbers 3:1).
Anyone with whom the Omnipresent engages to establish a nation or a family tree from him, the Omnipresent would also engage with him to write generations in his regard, as you find twelve instances of generations in the verses. The first: “These are the generations of the heavens and the earth” (Genesis 2:4); “this is the book of the generations of Adam” (Genesis 5:1); “these are the generations of Noah” (Genesis 6:9); “these are the generations of the sons of Noah” (Genesis 10:1): “these are the generations of Shem” (Genesis 11:10); “these are the generations of Teraḥ” (Genesis 11:27); “these are the generations of Ishmael” (Genesis 25:12); “Isaac” (Genesis 25:19); “Esau” (Genesis 36:1); “Jacob” (Genesis 37:2). These are ten generations with which the Holy One blessed be He engaged to create the world and to establish nations. And there are two people that the Omnipresent wrote their generationst, one for the royal dynasty and one for the priestly dynasty: “These are the generations of Peretz” (Ruth 4:18), to establish the royal dynasty from him, and “these are the generations of Aaron and Moses"(Numbers 3:1), for the priestly dynasty.

And these are the generations of Jacob born unto him in Padan-Aram. And the sons of Jacob ‎were twelve. The sons of Leah were: The first born Reuben, and Simeon, and Levi, and Judah, ‎and Issachar, and Zebulum, and Dinah their sister: And the sons of Rachel were: Joseph and ‎Benjamin. And the sons of Zilpah, Leah’s maid-servant, were: Gad and Asher. And the sons of ‎Bilhah were: Dan and Naphtali; these are the sons of Jacob which were born unto him in Padan ‎Aram. And Jacob with his sons and all belonging to him journeyed further and came to Mamre, ‎the same is Kirjath-Arba which is in Hebron, where Abraham and Isaac dwelt, and Jacob with ‎his sons with all belonging to him dwelt with his father in Hebron. And his brother Esau and his ‎sons, and all belonging ... to him went to the land of Seir and dwelt there, and had possessions ‎in the land of Seir, and the children of Esau were fruitful and multiplied exceedingly in the land ‎of Seir. And these are the generations of Esau that were born to him in the land of Canaan; ‎and the sons of Esau were five. And Adah bare to Esau his first born Eliphaz, and she also bare ‎to him Reuel. And Ahli bamah bare to him Jeush, and Yaalam and Korah. These are the children ‎of Esau who were born to him in the land of Canaan. And the sons of Eliphaz the son of Esau ‎were: Teman, and Omar, and Zepho, and Gatam, and Kenaz, and Amalex. And the sons of ‎Reuel were: Nachath, and Zerach, and Shamah, and Mizzah. And the sons of Jeush were: ‎Timnah, and Alva, and Jetheth. And the sons of Yaalam were: Alah, and Phinor, and Kenaz. ‎And the sons of Korah were: Teman, and Mibzar, and Magdiel, and Eram; these are the ‎families of the sons of Esau according to their dukes in the land of Seir. And these are the ‎names of the sons of Seir the Horite, inhabitants of the land of Seir: Lotan, and Shobal, and ‎Zibean, and Anah, and Dishon, and Ezer, and Dishan, seven sons.‎‏ ‏And the children of Lotan ‎were: Hori, and Heman, and their sister Timna, that is Timna who came to Jacob and his sons, ‎and they would not listen to her, and she went and became a concubine to Eliphaz the son of ‎Esau, and she bare to him Amalek.‎‏ ‏And the sons of Shobal were: Alvan, and Manahath, and ‎Ebal, and Shepho, and Onam.‎‏ ‏And the sons of Zibeon were: Ajah, and Anah, this is Anah who ‎found the Yemim in the wilderness when he fed the asses of Zibeon his father.‎‏ ‏And it came to ‎pass while he was feeding the asses of his father, driving them to the wilderness into pasture ‎as heretofore, and approaching one of the deserts on the sea shore opposite the wilderness ‎of the people, and be hold a very great storm came from the other side of the sea, and it ‎rested over the asses in the pasture and they were stunned and stood still all of them.‎‏ ‏And ‎after wards one hundred and twenty great and horrible animals emerged from the wilderness ‎on the other side of the sea, and they came all to the place of the asses and stood there.‎‏ ‏And ‎those animals were on their lower half after the shape of the sons of men, but the upper half ‎of some were in the shape of bears and some in the shape of apes, and they had tails behind, ‎hanging down from between the shoulders and sweeping the ground like the tails of the ‎dochiphath.‎

Chapter (58) 59: Prophets [1] The vision of Obadiah. "Thus says the Lord God concerning Edom (Jeremiah 49:7): We have heard a report from the Lord, and a messenger has been sent among the nations: 'Rise up! Let us rise against her for battle!'" (Jeremiah 49:14). When Jacob, our father, saw the leaders of Esau, he became afraid and began to say, "Who can stand up against all of them, so many kings and leaders, and I am but one person? How can I stand up against all of them?" Then the Holy One, blessed be He, said to him, "Do not be afraid. Look at what is behind you." "These are the generations of Jacob. Joseph" (Genesis 37:2). "Who can stand up against all of them?" "The smallest one among your children." "And the House of Jacob shall be fire and the House of Joseph a flame" (Obadiah 1:18). It is compared to a goldsmith who was sitting and doing his work, and his disciple was with him. The disciple raised his eyes and saw many camels loaded with straw. He began to wonder and said to his teacher, "Who can stand up against all of them?" His teacher replied, "One spark from the furnace can burn them all." So the Holy One, blessed be He, said to Jacob, "Are you afraid of them? One spark from you can burn them all," as it is stated, "Behold, they shall be as stubble, the fire shall burn them; they shall not deliver themselves from the power of the flame" (Isaiah 47:14). This refers to Joseph, as it is stated, "And the House of Joseph shall be a flame" (Obadiah 1:18). Therefore, "and he (Jacob) descended" (Genesis 36:1), the descent (interpreted as) the worst (possible scenario) that Jacob loses them all, and the descent of your children is combined against Esau. Even Obadiah, the lowest of all the prophets, takes revenge against Edom, as it is stated, "The vision of Obadiah. "Why has Yaakov descended?" (Obadiah 1:18)