2 Chronicles 23:2 Commentary - English Annotations on the Holy Bible by Matthew Poole

Gathered the Levites out of all the cities of Judah; partly because they could do this without any suspicion, upon pretence of some solemn feast; which time, it is probable, was chosen for this purpose; and partly because he knew them to be well affected to the cause of God and the king, to which they were obliged by the two firmest ties, conscience and interest.

The chief of the fathers of Israel, i.e. both of the two tribes, and of the ten tribes, all which are called Israel; and he useth the name of Israel rather than that of Judah, because there were now great numbers of the other tribes incorporated with Judah; and these he esteemed more faithful than many of Judah, having given better proofs of the truth of their religion than they; and therefore he picked out of the chief men of the other tribes as well as of Judah and Benjamin.