Remember that the priests were descendants of Jacob’s son Levi through Aaron, but the priests were not the only Levites. The rest of the Levitical family served as assistants to the priests. The priests were divided into twenty-four sections. Likewise, the Levites were divided into twenty-four sections. From among the Levites, three families were selected to be the musicians: Asaph, Heman, and Jeduthun. Their families were divided into twenty-four sections as well to correspond to the Priests and the other Levites.
Who decides who serves when?
It could have been that the wealthiest families, or the largest families, or the most talented families could have received preferential treatment, but to avoid just such a scenario, the families “cast lots” for their place in the order of service. You see it plainly in the list of chapter twenty-five: the lots are cast in the order of the families of Asaph, Jeduthun, Asaph, Jeduthun, Asaph, Heman, Asaph, Jeduthun, Heman . . . and so on.
Two points stand out about chapter twenty-five: First, music was to play an important part in temple worship. Further, this was not about entertainment, for the duty of the musicians was to “prophesy,” to teach and to remind Israel of her covenant with God. Musicians ministers need to remember this: your ministry is not to entertain, but to teach and remind.
The second lesson is that preferential treatment should not be a part of leadership. If it comes down to it, and choices must be made, drawing straws might be the best way – not to decide on qualified leaders – but to assign qualified leaders to areas of service.