1 Chronicles 23:5-7

ERV(i) 5 and four thousand were doorkeepers; and four thousand praised the LORD with the instruments which I made, [said David], to praise therewith. 6 And David divided them into courses according to the sons of Levi; Gershon, Kohath, and Merari. 7 Of the Gershonites; Ladan and Shimei.