As for the sons of Merari The third and youngest son of Levi:
thou shalt number them after their families, by the house of their fathers; which is the form of expression used of them all; (See Gill on Numbers 4:2).
27
All their work, whatever they carry and all their duties, will be done under the direction of Aaron and his sons. You are in charge of telling them everything they're supposed to carry.
28
This is the work of the Gershonite families in the tent of meeting. Ithamar, son of the priest Aaron, will be in charge of them.
29
"Register the Merarites by families and households.
30
Register all the men between the ages of 30 and 50 who are qualified to serve at the tent of meeting.
31
These are their duties as they work at the tent of meeting: They will carry the framework for the inner tent, the crossbars, posts, and sockets,