Genesis 25:29-33

And Jacob boiled pottage: and Esau came in from the field, and he was faint: and Esau said to Jacob, Feed me, I pray thee, with that same red pottage; for I am faint: therefore was his name called Edom. And Jacob said, Sell me first thy birthright. And Esau said, Behold, I am about to die: and what profit shall the birthright do to me? And Jacob said, Swear to me first; and he sware unto him: and he sold his birthright unto Jacob.