Numbers 7:10,11

And the princes offered for dedicating of the altar in the day that it was anointed, even the princes offered their offering before the altar.

The princes offered ..., х hamizbeeach (H4196)]. "Altar" is here used in the singular for the plural; because it is evident, from the kind of offerings, that the altars of burnt offering and incense are both referred to. This was not the first or proper dedication of those altars, which had been made by Moses and Aaron some time before. But it might be considered an additional dedication-those offerings being the first that were made for particular persons or tribes.

They shall offer ... Eastern princes were accustomed anciently, as they are in Persia still, on a certain yearly festival, to sit upon their thrones in great state, when the princes and nobles, from all parts of their dominions, appear before them with tributary presents, which form a large proportion of their royal revenue. And in the offering of all gifts or presents to great personages every article is presented singly and with ostentatious display. The tabernacle being the palace of their king, as well as the sanctuary of their God, the princes of Israel may be viewed, on the occasion under notice, as presenting their tributary offerings, and in the same manner of successive detail which accords with the immemorial usages of the East. A day was set apart for each, as much for the imposing solemnity and splendour of the ceremony as for the prevention of disorder and hurry; and it is observable that, in the order of offering, regard was paid to priority, not of birth, but of rank and dignity, as they were ranged in the camp-beginning at the east, proceeding to the south, then to the west, and closing with the north according to the course of the sun.