'Birthright' in the Bible

But Jacob replied, "First sell me your birthright."

"Look," said Esau, "I'm about to die! What use is the birthright to me?"

But Jacob said, "Swear an oath to me now." So Esau swore an oath to him and sold his birthright to Jacob.

Then Jacob gave Esau some bread and lentil stew; Esau ate and drank, then got up and went out. So Esau despised his birthright.

Esau exclaimed, "'Jacob' is the right name for him! He has tripped me up two times! He took away my birthright, and now, look, he has taken away my blessing!" Then he asked, "Have you not kept back a blessing for me?"