John Gill Commentary 1 Chronicles 9:14

"And of the Levites: Shemaiah the son of Hasshub, the son of Azrikam, the son of Hashabiah, of the sons of Merari;" — 1 Chronicles 9:14 (ASV)

And of the Levites
Having given an account of the two first classes of the people, the Israelites and priests, the author of the book now proceeds to the Levites, the third class; and the first mentioned is Shemaiah, whose ancestors, Hashub, Azrikam, and Hashabiah,

[were] of the sons of Merari ;
the third son of Levi.