Midrasch zu Bereschit 12:6

Esau said to Jacob: Divide all that my father has left into two portions, and I will choose (first), because I am the elder. || Jacob said: This wicked man has not satisfied his eye with wealth, as it is said, "Neither are his eyes satisfied with riches" (Eccles. 4:8). What did Jacob do? He divided all that his father had left as the one part, and the other part was to be the land of Israel and the Cave of Machpelah. What did Esau do? He went to Ishmael in the wilderness in order to consult him, as it is said, "And Esau went unto Ishmael" (Gen. 28:9). Ishmael said to Esau: The Amorite and the Canaanite are in the land, and Jacob trusts (in God) that he will inherit the land, therefore take all that thy father has left, and Jacob will have nothing.