The Sages relate that initially, the two sisters, Leah and Rachel, were designated for their two cousins, Esau and Jacob. Because Leah prayed to avoid her fate of marrying Esau, this did not occur.

Leah was intended to be married only to Esau, and Rachel to Jacob. Leah would sit at the crossroads and ask, concerning Esau, what his actions were. Passersby would tell her: He is a nefarious man, a shedder of blood. He robs passersby, he is covered with a cloak of red hair, he is wicked, he has performed all actions that are abominations to God. When Leah would hear that, she would weep and say: I and my sister Rachel emerged from the same womb; will Rachel be married to Jacob the righteous and I to Esau the wicked? She would weep and fast until her eyes grew tender; therefore, it is written: “Leah’s eyes were tender” (Genesis 29:17). “The Lord saw that Leah was hated” (29:31). He saw that Esau’s actions were hateful before her.(Tanĥuma, Vayetze)