1 Chronicles 23:11
Jahath was the oldest and Zizah the second oldest. Jeush and Beriah did not have many sons, so they were considered one family with one responsibility.
Treasury of Scripture Knowledge
Summary
And Jahath was the chief, and Zizah the second: but Jeush and Beriah had not many sons; therefore they were in one reckoning, according to their father's house.
Zizah
General references
Bible References
Zizah
1 Chronicles 23:10
The sons of Shimei: Jahath, Zina, Jeush, and Beriah. These were Shimei's sons -- four in all.
General references
Numbers 3:18
These are the names of the sons of Gershon by their families: Libni and Shimei.