Ezekiel 42:13-14

13Then he (the angel) said to me, “The north chambers and the south chambers, which are opposite the separate area, are the holy chambers where the priests who are close to the Lord shall eat the most holy offerings. There they shall place the most holy things—the grain offering, the sin offering, and the guilt offering—for the place is holy.

14When the priests enter [the Holy Place], they shall not go out from the sanctuary into the outer court unless they lay there their garments in which they minister, for these are holy (set apart). They shall put on other garments before they approach that which is for the people.”