1 Chronicles 23:2-5

David gathered all the leaders of Israel, along with the priests and Levites. He counted the Levites who were thirty years old and older. In all, there were thirty-eight thousand Levites. David said, “Of these, twenty-four thousand Levites will direct the work of the Temple of the LORD, six thousand Levites will be officers and judges, four thousand Levites will be gatekeepers, and four thousand Levites will praise the LORD with musical instruments I made for giving praise.”