וכפר אהרן על קרנתיו אחת בשנה ... קודש קדשים הוא לדי
Rashi explains that the Mizbayach, Altar, is a Kodesh Kodoshim, Holy of Holies Its sanctity is supreme, designated for this service exclusively. We derive from Rashi that the Mizbayach HaKetores, Incense Altar, is considered Kodesh Kodoshim, since no other service (the application of blood on the horns of the Mizbayach on Yom Kippur) was performed on it. (The daily Ketores, Incense, was also offered on it.) In his commentary to the pasuk, the Malbim posits that the focus of Kodesh Kodoshim is not the Mizbayach, but Aharon HaKohen. Thus, the Torah is informing us that Aharon Hakohen performed the service…