Numbers 4:31-33

31“Their only duty at the Tabernacle will be to carry loads. They will carry the frames of the Tabernacle, the crossbars, the posts, and the bases;

32also the posts for the courtyard walls with their bases, pegs, and ropes; and all the accessories and everything else related to their use. Assign the various loads to each man by name.

33So these are the duties of the Merarite clans at the Tabernacle. They are directly responsible to Ithamar son of Aaron the priest.”