I Chronicles 25:9

Now the first lot came forth for Asaph to Joseph,.... His second son to the preference of the firstborn, Ch1 25:2, the second to Gedaliah, who with his brethren and sons were twelve: and which must also be understood of Joseph, and supplied to him; for those being both in one verse, as Jarchi observes, it is but once mentioned, but must be supplied, or otherwise the number of two hundred and eighty eight could not be made up; the same is observed of all the other lots and courses to the end of the chapter as here, and therefore need no more remarks. Next: 1 Chronicles Chapter 26

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).