Matthew Henry on 1 Chronicles 23:1-23
Here we have, I. The crown entailed, according to the divine appointment, Ch1 23:1. David made Solomon king, not to reign with him, or reign under him, but only to reign after him. This he did, 1. When he was old and full of days. He was but seventy years old when he died, and yet he was full of days, satur dierum - satisfied with living in this world. When he found himself going off, he made provision for the welfare of the kingdom after his decease, and pleased himself with the hopeful prospect of a happy settlement both in church and state. 2. He did it in parliament, in a solemn assembly of all the princes of Israel, which made Adonijah's attempt to break in upon Solomon's title and set…
Read the whole note in the consoleJamieson-Fausset-Brown on 1 Chronicles 23:6
David divided them into courses among the sons of Levi--These are enumerated according to their fathers' houses, but no more of these are mentioned here than the twenty-four thousand who were engaged in the work connected with the Lord's house. The fathers' houses of those Levites corresponded with the classes into which they [JOSEPHUS, Antiquities] as well as the priests were divided (see on Ch1 24:20-31; Ch1 26:20-28).
Adam Clarke on 1 Chronicles 23:5
Four thousand praised the Lord - David made this distribution according to his own judgment, and from the dictates of his piety; but it does not appear that he had any positive Divine authority for such arrangements. As to the instruments of music which he made they are condemned elsewhere; see Amo 6:5, to which this verse is allowed to be the parallel.
John Gill on 1 Chronicles 23:6
And David divided them into courses among the sons of Levi,.... Into three classes, according to the number of them, which follow: namely:
Gershon, Kohath, and Merari; see Exodus 6:16.
Keil & Delitzsch on 1 Chronicles 23:6