Genesis 25:31-34

But Jacob said, “Sell me your birthright as of this day.” And Esau said, “Look, I am about to die; so what is this birthright to me?” Then Jacob said, “Swear to me as of this day.” So he swore to him, and sold his birthright to Jacob. And Jacob gave Esau bread and stew of lentils; then he ate and drank, arose, and went his way. Thus Esau despised his birthright.