Numbers 7:8

6And Moses took the wagons and the oxen, and gave them unto the Levites.

7Two wagons and four oxen he gave unto the sons of Gershon, according to their service:

8And four wagons and eight oxen he gave unto the sons of Merari, according unto their service, under the hand of Ithamar the son of Aaron the priest.

9But unto the sons of Kohath he gave none: because the service of the sanctuary belonging unto them was that they should bear upon their shoulders.

10And the princes offered for dedicating of the altar in the day that it was anointed, even the princes offered their offering before the altar.