Numbers 4:33
This is the service of the families of the sons of Merari, according to all their service, in the tabernacle of the congregation, under the hand of Ithamar the son of Aaron the priest. This is the service of the families of the sons of Merari, according to all their service, in the tabernacle of the congregation, under the hand of Ithamar the son of Aaron the priest.
Numbers 4:33 belongs to the assignment of the Levites to their tabernacle duties. The Levites erected the tabernacle and camped around it, and when Israel traveled they dismantled and carried the tabernacle and its sacred furnishings. Within that assignment the families of the sons of Merari were given responsibility for caring for and carrying the pillars, sockets, boards, and related parts of the tabernacle.
Their work was distinct from the duties of the other Levite divisions, for God specified who was to do each part of the work and the sacred tabernacle was not to be transported or handled indiscriminately. The Merarites performed all their service in the tabernacle of the congregation under the hand and direction of Ithamar, the son of Aaron the priest. This tabernacle service was an honored responsibility, given to the Levites in recognition of their faithfulness in carrying out God's order after the golden calf.
The careful order God established teaches organization and obedience. Each worker is to perform the duties assigned to him and leave another worker's work alone.