1 Chronicles 25:6

“Afterward you will come to the hill of God where the Philistine garrison is; and it shall be as soon as you have come there to the city, that you will meet a group of prophets coming down from the high place with harp, tambourine, flute, and a lyre before them, and they will be prophesying.

And with them were Heman and Jeduthun, and the rest who were chosen, who were designated by name, to give thanks to Yahweh, because His lovingkindness endures forever.

He then caused the Levites to stand in the house of Yahweh with cymbals, with harps, and with lyres, according to the command of David and of Gad the king’s seer, and of Nathan the prophet; for the command was from Yahweh by the hand of His prophets.

From the outside to the inner gate were chambers for the singers in the inner court, one of which was at the side of the north gate, with its front toward the south, and one at the side of the south gate facing toward the north.