1 Chronicles 25:21

The fourteenth to Mattithiah, he, his sons, and his brethren, were twelve:

The verse reflects a carefully studied plan for assigning special duties to the men best fitted for them, a plan perfected as Solomon took the throne and extended to every branch of the priests and Levites, to the civil officers, and to the army. It records the fourteenth of the twenty-four courses into which the four thousand temple musicians were divided. That fourteenth course was Mattithiah's, and it numbered twelve in all when he was counted together with his sons and his brethren. Each such course was led by twelve men who were especially instructed and skillful in the use of musical instruments.