“It was when Rachel bore Joseph, Jacob said to Laban: Release me, and I will go to my place and to my land” (Genesis 30:25). “It was when Rachel bore Joseph” – when Joseph was born, Esau’s adversary was born,12Joseph is Esau's adversary. See Bava Batra 123b. as it is stated: “Jacob said to Laban: Release me, and I will go to my place and to my land,” as Rabbi Pinḥas said in the name of Rabbi Shmuel bar Naḥman: It is a tradition that Esau will fall only into the hand of the descendants of Rachel. That is what is written: “Will the young of the flock not drag them?”13"Them" in the verse refers to Edom. (Jeremiah 49:20) – why does it call them “the young of the flock”? It is because they were the youngest of the tribes.
Joseph's Birth Gave Jacob Courage to Face Esau
Bereshit Rabbah 73:7