(3-4) Reuben... — The sons of the legitimate wives are placed first, then those of the concubines. Leah has precedence over Rachel; Bilhah over Zilpah. The children of each wife and concubine are given in order of seniority. The omission of Joseph from the list is explained in the last clause of Exodus 1:5.
Related Commentaries of Exodus 1:3
Exodus 1:3-4
3 Issachar, Zebulun, and Benjamin,
4 Dan, and Naphtali, Gad, and Asher.