1 Chronicles 25:1-2

1Moreover David and the captains of the army separated for the service some of the sons of Asaph, of Heman, and of Jeduthun, who should prophesy with harps, stringed instruments, and cymbals. And the number of the skilled men performing their service was:

2Of the sons of Asaph: Zaccur, Joseph, Nethaniah, and Asharelah; the sons of Asaph were under the direction of Asaph, who prophesied according to the order of the king.