3 offered and brought their offerings before the Lord, six covered wagons and twelve oxen, a wagon for every two of the leaders, and for each one an ox; they offered them before the tabernacle.

Matthew Henry's Commentary on Numbers 7:3

Commentary on Numbers 7:1-9

(Read Numbers 7:1-9)

The offering of the princes to the service of the tabernacle was not made till it was fully set up. Necessary observances must always take place of free-will offerings. The more any are advanced, the greater opportunity they have of serving God and their generation. No sooner was the tabernacle set up, than provision is made for the removal of it. Even when but just settled in the world, we must be preparing for changes and removes, especially for the great change.