1 Chronicles 25:1-31

In chapter twenty-five.

Moreover David and the captains of the host separated to the service of the sons of Asaph, and Heman, and Jeduthun, those who should prophesy with harps, with psalteries, and with cymbals: and the number of the workmen according to their service was (1 Chronicles 25:1):

Now they were commissioned to prophesy, which does not mean foretelling necessarily, but forth telling the works of God. So the music was declaring the greatness, the glory, the power, the beauty of God. So you that are musicians, think about that when you go to write your music. Let it express the greatness, the glory, the power of God. Speaking forth the glories of God in the music. And of course, so much of our hymnology is involved with "a mighty fortress is our God, a bulwark never failing" and all. And declaring the greatness. "All hail the power of Jesus' name." And declaring the glories, the power of God. And that's really what the music is to do, is to speak forth the praises and the glory of God. And so these men that were appointed that they should prophesy with their harps and all. That is, speaking forth God's glory.
Now verse six.

And all of these were under the hands of the fathers for song in the house of the LORD, with the cymbals, the psalteries, the harps, for the service of the house of God, according to the king's order to Asaph, and all. So the number of them, with their brethren that were instructed in the songs of the LORD, even all that were cunning, was two hundred and eighty-eight (1 Chronicles 25:6-7).

Musicians that were cunning and used their instruments in praising the Lord.

And then they cast the lots, into again twenty-four orders. The first lot came forth from Asaph to Joseph (1 Chronicles 25:8-9):

And it goes on to the various orders that were developed in the cast of lots. "