For the dedicating of the altar Both of burnt-offerings and of incense, as appears from the matter of the offerings here said to be made. This is not meant of the first dedication of them, for they had been dedicated or consecrated before this time by Moses and Aaron, with solemn ceremonies which lasted seven days; (Exodus 29:37; Leviticus 8:11;) but for a further dedication of them, or the first application of them to their proper uses, these being the first offerings that were made for any particular persons or tribes. In the day That is about the time when it was anointed.
Related Commentaries of Numbers 7:10
Numbers 7:10
10 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.