The rights of the firstborn

“The sons of Reuben the firstborn of Israel (he was the firstborn, but when he defiled his father’s marriage bed, his rights as firstborn were given to the sons of Joseph son of Israel; so he could not be listed in the genealogical record in accordance with his birthright, and though Judah was the strongest of his brothers and a ruler came from him, the rights of the firstborn belonged to Joseph)” 1 Chronicles 5:1-2
Throughout the Old Testament, we read about the rights of the firstborn. These were intended to be bestowed upon the eldest son of the family. In the case of Jacob’s children, Reuben was his firstborn, born to his wife Leah. The rights of the firstborn were three-fold. Firstly and most importantly, was the responsibility for the eldest son to be the leader of the family. Secondly, the firstborn received a double portion of the father’s inheritance, compared to his brothers. Thirdly, the firstborn was often given a special blessing by the father on his deathbed.
However, we do read in Scriptures of instances where the eldest son was passed over in terms of being given these rights as firstborn. Isaac is treated as the firstborn son of Abraham, although Ishmael was actually born first. Esau was the firstborn son of Isaac, yet both his rights and his blessing were given to Jacob instead.
Like Esau, Reuben forfeited his rights by his own actions. In Gen. 35:22 we read how Reuben engaged in sexual intercourse with Bilhah, his father’s concubine (and mother to two of his half-brothers, Dan and Naphtali). He was most likely following a local custom where a son seeking to usurp the father’s authority would sleep with his concubines. However, for Reuben it backfired. The double portion and the blessing that should have been his, passed to Joseph, Jacob’s firstborn by his wife Rachel. This is why we don’t read of the ‘tribe of Joseph’, because Joseph’s descendants were counted as two tribes: those of Ephraim and Manasseh (Joseph’s sons). Similarly, Reuben forfeited the right to lead the family: this passed to Judah, Jacob’s fourth son to Leah (passing over Simeon and Levi, who had taken vengeance into their own hands in defending their sister Dinah, see Gen. 34). Thus Judah had the promise of being the ruling tribe in Israel, realised through David and his dynasty.