1 Chronicles 3-5

Reuben was the oldest son of Jacob, and by tradition the birthright belonged to him, which speaks of the position of leadership, or paterfamilias.  However, because he slept with one of his father’s concubine, that honor was stripped from him.  Likewise, Simeon and Levi (2nd and 3rd in birth order) lost that right of succession because of the murders they committed against Shechem.  Judah was 4th, and took the leadership role of the family, even though Jacob gave the birthright to Joseph, and the double portion of his inheritance was included for Joseph’s sons (Ephraim and Manasseh).

Chapter 5 gives the genealogy of Reuben, and also describes the inheritance of Reuben, Gad, and the half tribe of Manasseh.  These three tribes were allotted land on the east side of the Jordan River, whereas all of the rest of the tribes (plus the other half of Manasseh) received their inheritance in the land of Canaan, to the west of the Jordan.