Ezekiel 40:44-46

44Outside the inner gate in the inner court were chambers for the singers, one of which was at the side of the north gate, facing south. The one at the side of the east gate faced north.

45He said to me, “This chamber that faces toward the south is for the kohanim who keep charge of the House.

46The chamber that faces toward the north is for the kohanim who keep charge of the altar. These are the sons of Zadok, those from the sons of Levi who come near to Adonai to minister to Him.”