Numbers 7:2-3

2Then 1the leaders of Israel, the heads of their fathers’ households, 2made an offering (they were the leaders of the tribes; they were the ones who 3were over the 4numbered men).

3When they brought their offering before the Lord, six 5covered carts and twelve oxen, a cart for every two of the leaders and an ox for each one, then they presented them before the tabernacle.