Numbers 4:31-33

31And this shall be the charge of their burden, according to all their service in the tent of meeting: the boards of the tabernacle, and the bars thereof, and the pillars thereof, and bases thereof,

32and the pillars of the court round about, and their bases, and their pegs, and their cords, all their instruments, according to all their service; and by name ye shall number to them the materials which are their charge to carry.

33This is the service of the families of the sons of Merari, according to all their service in the tent of meeting, under the hand of Ithamar the son of Aaron the priest.