Numbers 7:4

That the princes of Israel, heads of the house of their fathers, who were the princes of the tribes, and were over them that were numbered, offered:

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.

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.