Ezekiel 40:44-46

44And outside the inner gate were two cells in the inner court, one at the side of the north gate, and its front towards the south; the other was at the side of the south gate, the front towards the north.

45And he said unto me, This cell whose front is towards the south is for the priests, the keepers of the charge of the house.

46And the cell whose front is toward the north is for the priests, the keepers of the charge of the altar. These are the sons of Zadok, those who, from among the sons of Levi, approach unto Jehovah to minister unto him.