Mishnayos Orlah Perek 2 Mishnah 17

בשר קדשי קדשים – it is forbidden to foreigners (i.e., non-Kohanim), even those who are pure. The meat of lesser Holy Things is permitted to pure foreigners but is forbidden to impure foreigners, and it was cooked with meat eaten for satisfying the appetite (i.e., secular meal of meat as opposed to sacrificial meals), unconsecrated meat is permitted even to those [foreigners] who are impure, and there is within it enough to nullify each person on his own, and it combines to prohibit to those who are ritually impure, even according to Rabbi Shimon for the [meat] of the Holy of Holies and the lesser Holy things are one type, as we stated above (see Mishnah 1 of this chapter) regarding Terumah and Hallah and First Fruits. And they are permitted to ritually pure foreigners (i.e., non-Kohanim) even according to the Rabbis for the [meat of] the Holy of Holies has nothing in them to prohibit [their use].