Numbers 7:3 – 9
New International Version (NIV1984)
3 They brought as their gifts before the Lord six covered carts and twelve oxen — an ox from each leader and a cart from every two. These they presented before the tabernacle.
4 The Lord said to Moses, 5 “Accept these from them, that they may be used in the work at the Tent of Meeting. Give them to the Levites as each man’s work requires.”
6 So Moses took the carts and oxen and gave them to the Levites. 7 He gave two carts and four oxen to the Gershonites, as their work required, 8 and he gave four carts and eight oxen to the Merarites, as their work required. They were all under the direction of Ithamar son of Aaron, the priest. 9 But Moses did not give any to the Kohathites, because they were to carry on their shoulders the holy things, for which they were responsible.
From BibleGateway.com: http://www.biblegateway.com/passage/?search=Numbers 7:3 – 9&version=NIV1984