And Jacob said: "Sell me this day thy birthright".

"And Esau said, Behold I am at the point to die: and what profit shall this birthright do to me?
And Jacob said, Swear to me this day; and he sware unto him: and he sold his birthright unto Jacob.

Then Jacob gave Esau bread and pottage of lentils; and he did eat and drink, and rose up, and went his way: thus Esau despised his birthright." -- Genesis 25:27-34.
[109]Genuine, real right and title to the birthright was now Jacob's for two good and sufficient reasons: (1) because it was so ordered by the Lord before his birth, as above stated; and (2) because he had bought it in an open and fair transaction with his brother Esau.

These two brothers were not mere children at this time.

They were past forty years of age (Genesis 26:34), both capable of entering into a contract; and they made a contract which was binding upon both.
[110]Notwithstanding these two good reasons why Jacob was justly entitled to the birthright, Esau attempted to deprive him of it.