What Does “Birthright” Mean in the Bible?
The rights of the oldest son: he inherited more and was head of the family. Esau sold it to Jacob.
Where it appears in the Bible
Genesis 25:31-34
What the Bible says
Genesis 25:31-34
31And Jacob said to him: Sell me thy first birthright. 32He answered: Lo I die, what will the first birthright avail me? 33Jacob said: Swear therefore to me. Esau swore to him, and sold his first birthright. 34And so taking bread and the pottage of lentils, he ate, and drank, and went his way; making little account of having sold his first birthright.
Douay-Rheims Bible (Challoner revision), public domain.
Source: RAE, “primogenitura”; Genesis 25:29-34