The tribes are listed here in accordance with Jacob’s two wives—Leah and Rachel—and their handmaids Zilpah and Bilhah. Thus, the six sons of Leah are listed first (with the exclusion of Levi); the two sons of Rachel second; the sons of Zilpah and Bilhah are combined in third place. The particular order of the tribal list appears with some variation in the book of Numbers, as the particular practical purpose of each list will vary. The purpose here is merely to enlist the assistants that God had appointed for Moses from every tribe.
5 And these are the names of the men who shall assist you. From Reuben, Elizur the son of Shedeur;