'Birthright' in the Bible

And Jacob said, First of all give me your birthright.

And Esau said, Truly, I am at the point of death: what profit is the birthright to me?

And Jacob said, First of all give me your oath; and he gave him his oath, handing over his birthright to Jacob.

Then Jacob gave him bread and soup; and he took food and drink and went away, caring little for his birthright.

And he said, Is it because he is named Jacob that he has twice taken my place? for he took away my birthright, and now he has taken away my blessing. And he said, Have you not kept a blessing for me?