I Chronicles 25:3

Of Jeduthun,.... Or Ethan, the sons of Jeduthun: Gedaliah and Zeri; called Izri, Ch1 25:11, and Jeshaiah, Hashabiah, and Mattithiah, six; whereas five only are mentioned; it may be thought that Shimei, Ch1 25:17 is the sixth, he not being mentioned elsewhere; it is a tradition of the Jews, that his mother was now with child of him, and it being foreseen by the Holy Spirit that he would be the chief of a course, the number six is given, as Jarchi observes; but rather, as Kimchi, he was young, and not fit to sing, yet was chosen the head of a course, until he was grown up and fit for it; to these six came up the second, fourth, eighth, twelfth, fourteenth, and tenth lots, Ch1 25:9 and these were under the hands of their father Jeduthun; to instruct and direct them, and appoint their service to them: who prophesied with a harp; or sung a prophetic psalm or hymn on that: to give thanks, and to praise the Lord; for what he had done and promised, and foretold he would do for his people.

David, having settled the courses of these Levites that were to attend the priests in their ministrations, proceeds, in this chapter, to put those into a method that were appointed to be singers and musicians in the temple. Here is, I. The persons that were to be employed, Asaph, Heman, and Jeduthun (Ch1 25:1), their sons (Ch1 25:2-6), and other skilful persons (Ch1 25:7). II. The order in which they were to attend determined by lot (v. 8-31).