IV.
(2) Of the sons of Kohath... — Kohath appears to have been the second son of Levi (Numbers 3:17), but the Kohathites here stand first because Moses and Aaron belonged to them, and it was their office to bear the Ark.
Related Commentaries of Numbers 4:2
Numbers 4:2
2 Take the sum of the sons of Kohath from among the sons of Levi, after their families, by the house of their fathers,