Numbers 1:20
And the children of Reuben, Israel’s eldest son, by their generations, after their families, by the house of their fathers, according to the number of the names, by their polls, every male from twenty years old and upward, all that were able to go forth to war;
Cross-references
Numbers 1:18 describes the census procedure, the same process applied to Reuben here.
Numbers 26:5-7 lists Reuben's descendants from the second census, paralleling this first census record for the same tribe.
Numbers 2:10 assigns the camp position for Reuben's tribe, whose genealogy is listed here.
Genesis 46:9 lists Reuben's four sons, the same clans enumerated in the census here.
Genesis 49:3 declares Reuben as Jacob's firstborn, the same status mentioned here for the tribal census.
Genesis 49:4 recounts Reuben's sin that cost him his birthright, explaining why the firstborn blessing later transferred to Joseph.
1 Chronicles 5:1 clarifies that Reuben lost his birthright to Joseph's sons, though he remains the firstborn by chronology.
Genesis 35:22 records Reuben's sin with Bilhah, the event that cost him his birthright, alluded to in the census context.
Exodus 30:14 establishes the age of twenty for census participation, the same threshold used here for military enrollment.
Genesis 29:32 records Reuben's birth, the origin of the tribe counted here.
Genesis 46:8 also names Reuben as Jacob's firstborn when the family entered Egypt.