The firstborn or firstborn son (Hebrew בְּכוֹר bəḵōr) is an important concept in Judaism. The role of firstborn son carries significance in the redemption of the first-born son, in the allocation of a double portion of the inheritance, and in the prophetic application of "firstborn" to the nation of Israel.
The semitic root B-K-R means "early" or "first" in Ancient Near East semitic languages. Classical Hebrew contains various verbs from the B-K-R stem with this association. The plural noun bikkurim (vegetable firstfruits) also derives from this root. The masculine noun bekhor, firstborn, is used of sons, as "Canaan begat Sidon his firstborn" (Genesis 10:15), whereas the feminine noun, and female equivalent, is bekirah (בְּכִירָה), first-born daughter, such as Leah (Genesis 29:26). Derived from bechor is the qualitative noun bekhorah "birthright" (בְּכוֹרָה), related to primogeniture, such as that which Esau sold to Jacob. In the plural this qualitative noun "birthright" can also mean "firstlings", as when Abel brought out the "firstborn" (bekhorot feminine plural בְּכֹרֹות) of his flock to sacrifice (Genesis 4:4).
The earliest account of primogeniture to be widely known in modern times involved Isaac's son Jacob being born second (Genesis 25:26) and Isaac's son, Esau being born first (Genesis 25:25) and entitled to the "birthright", but eventually selling it to Isaac's second son, Jacob, for a small amount of food (Genesis 25:31-34) A similar transfer is shown by the writer of 1 Chronicles 5:1-2 where, although the tribe of Judah prevailed above their brethren, nevertheless the "birthright", the double portion of two tribal allotments, was Joseph's.