Nehemiah 12:45
And they performed the service of their God and the service of purification, as did the singers and the gatekeepers, according to the command of David and his son Solomon.
1 Chronicles 25:1-26
David and the chiefs of the service also set apart for the service the sons of Asaph, and of Heman, and of Jeduthun, who prophesied with lyres, with harps, and with cymbals. The list of those who did the work and of their duties was:
1 Chronicles 23:28
For their duty was to assist the sons of Aaron for the service of the house of the LORD, having the care of the courts and the chambers, the cleansing of all that is holy, and any work for the service of the house of God.
2 Chronicles 23:6
Let no one enter the house of the LORD except the priests and ministering Levites. They may enter, for they are holy, but all the people shall keep the charge of the LORD.