Ezekiel 40:44-46

44And without the inner gate were chambers for the singers in the inner court, which was at the side of the north gate; and their prospect was toward the south; one at the side of the east gate having the prospect toward the north. 45And he said unto me, This chamber, whose prospect is toward the south, is for the priests, the keepers of the charge of the house; 46and the chamber whose prospect is toward the north is for the priests, the keepers of the charge of the altar: these are the sons of Zadok, who from among the sons of Levi come near to Jehovah to minister unto him.