the singers

1 Chronicles 6:31-33
These are the men David put in charge of the music in the house of the LORD after the ark rested there. . . .

1 Chronicles 15:16-22
David also told the leaders of the Levites to appoint their relatives as singers to raise their voices with joy, accompanied by musical instruments--harps, lyres, and cymbals. . . .

1 Chronicles 16:4-6
David appointed some of the Levites to minister before the ark of the LORD, to celebrate, to give thanks, and to praise the LORD, the God of Israel. . . .

1 Chronicles 25:1
Additionally, David and the commanders of the army set apart some of the sons of Asaph, Heman, and Jeduthun to prophesy with the accompaniment of lyres, harps, and cymbals. The following is the list of the men who performed this service:

Ezra 7:24
And be advised that you have no authority to impose tribute, duty, or toll on any of the priests, Levites, singers, doorkeepers, temple servants, or other servants of this house of God.

were free

Nehemiah 11:17, 22, 23
Mattaniah son of Mica, the son of Zabdi, the son of Asaph, who led in thanksgiving and prayer; Bakbukiah, second among his associates; and Abda son of Shammua, the son of Galal, the son of Jeduthun. . . .

they, etc.

Psalm 134:1, 2
Come, bless the LORD, all you servants of the LORD who serve by night in the house of the LORD! . . .

Psalm 135:1-3
Hallelujah! Praise the name of the LORD. Give praise, O servants of the LORD, . . .