Although the incense altar is to be grouped with the other "vessels of service," there is something special about it that sit aside from them and requires that it be placed in a kind of appendix adjacent to the main command. Early and later commentators alike have sought this unique quality of the incense altar, and their conclusions may be categorized in two groups, each of which can be further subdivided into two. Some point to a characteristic that diminishes the importance of the incense altar in relation to the other vessels of the Mishkan, or one that diminishes the significance of the mitzva of incense in relation to the other services performed in the Mishkan. Others relate the uniqueness of the incense altar to its added significance, or to the special significance of the service of the incense.

Courtesy of the Virtual Beit Midrash, Yeshivat Har Etzion