'Birthright' in the Bible

Jacob said, "First, sell me your birthright."

Esau said, "Behold, I am about to die. What good is the birthright to me?"

Jacob said, "Swear to me first." He swore to him. He sold his birthright to Jacob.

Jacob gave Esau bread and stew of lentils. He ate and drank, rose up, and went his way. So Esau despised his birthright.

He said, "Isn't he rightly named Jacob? For he has supplanted me these two times. He took away my birthright. See, now he has taken away my blessing." He said, "Haven't you reserved a blessing for me?"

They sat before him, the firstborn according to his birthright, and the youngest according to his youth, and the men marveled one with another.