Numbers 7:7-11

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

And 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.

But 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.

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

And the LORD said unto Moses, They shall offer their offering, each prince on his day, for the dedicating of the altar.