Charles Ellicott Commentary 1 Chronicles 23:5

"and four thousand were doorkeepers; and four thousand praised Jehovah with the instruments which I made, [said David], to praise therewith." — 1 Chronicles 23:5 (ASV)

Moreover four thousand were porters. —Literally, and four thousand (are to be) warders. (Compare 1 Chronicles 9:21–27.) Reuss thinks 4,000 warders too many; but the different clans went on duty in turn.

And four thousand praised the Lord ...—Rather, and four thousand (are to be) praising the Lord with the instruments that I have made for praising. (On “praising,” see 1 Chronicles 16:4.) We have here an interesting reference to the fact that David was not only a minstrel and inspired psalmist, but also an inventor of stringed instruments. So the prophet Amos (1 Chronicles 6:5) speaks of the effeminate nobles of Israel, who prattle on the mouth of the nebel, that invent themselves instruments of music, like David. The reference is repeated in Nehemiah 12:36.

Which I have made. —This expression proves that 1 Chronicles 23:4–5 should be within inverted commas, as representing a spoken decree of David. Ewald thinks that the narrative is interrupted in 1 Chronicles 23:5 by a fragmentary quotation from an ancient poet who speaks in the name of Jehovah, characterising the musicians as “those whom I have formed to sing my praise.” (But see 2 Chronicles 7:6.)