John Gill Commentary 2 Samuel 24

And again the anger of the Lord was kindled against Israel ,
&c.] It had been kindled, and appeared before in sending a three years' famine among them for Saul's ill usage of the Gibeonites, (2 Samuel 21:1); and now it broke forth again, either for some secret sins committed, as Kimchi suggests, or for the rebellion of Absalom, and the insurrection of Sheba, in which multitudes of them joined; so Abarbinel; no doubt there was cause for it, though it is not expressed:

and he moved David against them ;
not the Lord, but Satan, as may be supplied from (1 Chronicles 21:1); or "it moved him"; the anger of the Lord, as the last mentioned writer interprets it; or the heart of David, as Ben Gersom; that is, the evil imagination of his heart, as Kimchi; the Lord left him to the corruption of his nature, sometimes called Satan, (2 Corinthians 12:7); which wrought powerfully in him, and stirred him up to take a step contrary to the interest of Israel, and what was prejudicial to them, as the event showed: it moved him to say; to Joab and his captains:

go, number Israel and Judah :
not all the individuals, but such as were fit for war, able to bear arms, see (2 Samuel 24:9) .

For the king said to Joab the captain of the host, which [was]
with him
Or who was with him, even Joab, who was now at court, and was a counsellor of David, as well as his general; or which army was with Joab, a standing army he had the command of:

go now through all the tribes of Israel, from Dan even to Beersheba ;
from the northern part of the land of Israel to the southern part of it, and this course was accordingly steered, (2 Samuel 24:6 2 Samuel 24:7) ;

and number ye the people, that I may know the number of the people ;
so that this appears to be done not through any urgent necessity, but merely out of curiosity, and to gratify the pride of his heart, and please himself with the thought of ruling such a numerous people, and brag of their numbers to other nations, and place his confidence therein; and no wonder it was displeasing to the Lord.

And Joab said unto the king
Not so rudely and insolently as he did on account of his mourning for Absalom, but in a more modest, decent, and polite manner:

now the Lord your God add unto the people (however many they are) an
hundredfold ;
he wished his subjects were an hundred times more numerous than they were:

and that the eyes of my lord the king may see [it] ;
that he might live to see with his own eyes so great an increase:

but why does my lord the king delight in this thing ?
he being now old, and therefore it might seem strange to indulge such curiosity, pride, and vanity, and besides quite needless and useless: the numbering of them would not make them more or less; and they were all the king's servants, who were ready to obey him whenever he needed them, whether numbered or not; and it might be prejudicial to them, and bring down the wrath of God upon them, as well as be a troublesome and expensive business; all which, though not expressed here, is hinted at in (1 Chronicles 21:3) .

Notwithstanding the king's word prevailed against Joab, and
against the captains of the host
Who it seems were of the same mind with Joab, and were against numbering the people, yet their arguments and remonstrances were of no avail with the king; he was determined it should be done, and laid his commands upon them to do it, which they were obliged to comply with:

and Joab and the captains of the host went out from the presence of the
king, to number the people of Israel ;
seeing him resolute and determined, they submitted, took his orders, and set out to execute them.

And they passed over Jordan
To take the number of the tribes of Reuben and Gad and the half tribe of Manasseh first:

and pitched in Aroer ;
for it seems that Joab and the captains had the army with them, and the several captains under their command, partly to assist in numbering the people, and partly to keep them in awe, lest they should oppose them, not knowing what was the design of all this Aroer was a city given to the tribe of Gad, and rebuilt by them, (Numbers 32:34) ;

on the right side of the city ;
that is, of Aroer, the south side of it, as the Targum, did Joab and his army pitch:

that [lieth] in the midst of the river of Gad ;
which was the river Arnon, so called now from the tribe of Gad, which possessed it, and so the Targum, in the midst of the river of the tribe of Gad; for in the midst of the river Arnon Aroer lay, see (Joshua 13:9) ;

and toward Jazer ;
another city given to the Gadites, (Numbers 32:3Numbers 32:35) ; and, according to Bunting ^F21 , was sixteen miles from Aroer.

FOOTNOTES:

• F21: Travels p. 147.