Numbers 7:4-9

Then the LORD said to Moses, “Accept these from them, that they may be used in the service of the tent of meeting, and give them to the Levites, to each man according to his service.” So Moses took the wagons and the oxen and gave them to the Levites. Two wagons and four oxen he gave to the sons of Gershon, according to their service. And four wagons and eight oxen he gave to the sons of Merari, according to their service, under the direction of Ithamar the son of Aaron the priest. But to the sons of Kohath he gave none, because they were charged with the service of the holy things that had to be carried on the shoulder.