He moved David against them - God could not be angry with David for numbering the people if he moved him to do it; but in the parallel place (Ch1 21:1) it is expressly said, Satan stood up against Israel, and provoked David to number Israel. David, in all probability, slackening in his piety and confidence toward God, and meditating some extension of his dominions without the Divine counsel or command, was naturally curious to know whether the number of fighting men in his empire was sufficient for the work which he had projected. See more on Sa2 24:10 (note). He therefore orders Joab and the captains to take an exact account of all the effective men in Israel and Judah. God is justly displeased with this conduct, and determines that the props of his vain ambition shall be taken away, either by famine, war, or pestilence.

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, Sa2 24:6,

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.