The twentieth to Eliathah, he, his sons, and his brethren, were twelve:
The verse belongs to David's careful organization of the sanctuary musicians into set courses. Under that arrangement the service of song was ordered and assigned rather than left to chance, with each course having its place in the sanctuary work. The musicians as a whole were led by twelve men set apart for this leadership. Those twelve leaders were specially instructed and skilled in playing their instruments, so that ability and training qualified them to direct the music.
The verse belongs to David's careful organization of the sanctuary musicians into set courses. Under that arrangement the service of song was ordered and assigned rather than left to chance, with each course having its place in the sanctuary work. The musicians as a whole were led by twelve men set apart for this leadership. Those twelve leaders were specially instructed and skilled in playing their instruments, so that ability and training qualified them to direct the music.