Singing Work

[1 Chron. 6:31] And these are they whom David set over the service of song in the house of the L-D, after that the ark had rest.
Service of song, the importance of this service is shown by the long genealogies given for the lead singers, Heman, Asaph, and Ethan (or Jeduthan). Each one goes all the way back to Levi, the son of Jacob. Herman, is the grandson of Samuel the prophet. Though Samuel’s son Joel did not follow the L-rd, Joel’s son Herman led the service of son in the Tabernacle of David.
David, by special commission and direction from G-d, new-modeled the Levites, as we shall find in the latter part of this book. Here we are told what the work was which he assigned them,
Singing-work. David was raised up on high to be the sweet psalmist of Israel (2 Sa. 23:1), not only to pen psalms, but to appoint the singing of them in the house of the L-d (not so much because he was musical as because he was devout), and this he did after that the ark had rest. While that was in captivity, obscure, and unsettled, the harps were hung upon the willow-trees: singing was then thought unseasonable (when the bridegroom is taken away they shall fast); but the harps being resumed, and the songs revived, at the bringing up of the ark, they were continued afterwards, for we should rejoice as much in the prolonging of our spiritual privileges as in the restoring of them. When the service of the ark was much superseded by its rest they had other work cut out for them (for Levites should never be idle) and were employed in the service of song, thus when the people of G-d come to the rest which remains for them above they shall take leave of all their burdens and be employed in everlasting songs.
We have here an account of the three great masters who were employed in the service of the sacred song, with their respective families; for they waited with their children, that is, such as descended from them or were allied to them. Heman, Asaph, and Ethan, were the three that were appointed to this service, one of each of the three houses of the Levites, that there might be equality in the distribution of this work and honour, and that every one might know his post, such an admirable order was there in this choir service.
Of the house of Kohath was Heman with his family, a man of a sorrowful spirit, if it be the same Heman that penned the 88th psalm, and yet a singer. He was the grandson of Samuel the prophet, the son of Joel, of whom it is said that he walked not in the ways of Samuel (1 Sa. 8:2, 3); but it seems, though the son did not, the grandson did. Thus does the blessing entailed on the seed of the upright sometimes pass over one generation and fasten upon the next. And this Heman, though the grandson of that mighty prince, did not think it below him to be a preceptor in the house of G-d. David himself was willing to be a door-keeper.
Those of them who were endowed with musical tastes and talents were employed in various other departments of the Temple service.