Numbers 4:29-33

29Next, count the sons of Merari, according to their families and their ancestral houses,

30sons 30 years old and upward to 50, everyone coming to work in the service of the Tent of Meeting.

31This is their task in the service of the Tent of Meeting: the frames of the Tabernacle, its crossbars, posts and bases,

32as well as the posts of the surrounding courtyard, plus their bases, tent pegs, ropes, and all their paraphernalia with everything related to their operation. Assign to them by name their duties and tasks.

33This is the service of the families of the sons of Merari as they work under the direction of Ithamar son of Aaron the kohen.”