Albert Barnes Commentary 1 Chronicles 2:1

"These are the sons of Israel: Reuben, Simeon, Levi, and Judah, Issachar, and Zebulun," — 1 Chronicles 2:1 (ASV)

The sons of Israel - The order of the names here approximates an order determined by legitimacy of birth. A single change—the removal of Dan to the place after Benjamin—would give the following result:

1. The six sons of the first wife, Leah.
2. The two sons of the second wife, Rachel.
3. The two sons of the first concubine, Bilhah.
4. The two sons of the second concubine, Zilpah.

Dan’s undue prominence can perhaps be explained by his occupying the seventh place in the “blessing of Jacob” (Genesis 49:16).