1 Chronicles 23:3-6

31Now the Levites were counted from thirty years old and upward, and 2their number by 3head count of men was thirty-eight thousand. 4Of these, twenty-four thousand were 4to oversee the work of the house of the Lord; and six thousand were 5officers and judges, 5and four thousand were gatekeepers, and 6four thousand were praising the Lord with the instruments which 7David made for giving praise. 6David divided them into divisions 8according to the sons of Levi: Gershon, Kohath, and Merari.