It seems impossible to determine who these servants, singers, the Nethinim (“temple servants”) were. Other passages in Ezra speak of singers of the House of Asaph [a Levite descended from Kohath] (Ezra 2:41), porters of the house of Shallum (v.42), singers, porters, Nethinim (v.70).
The ones in vv.55-58 are specifically talking about Solomon’s servants, singers, etc.
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