Numbers 7:3-7

And they brought their offering before the LORD, six covered wagons, and twelve oxen; a wagon for two of the princes, and for each one an ox: and they brought them before the tabernacle.

And the LORD spake unto Moses, saying,

Take it of them, that they may be to do the service of the tabernacle of the congregation; and thou shalt give them unto the Levites, to every man according to his service.

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

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