Joab gave the sum. The totals given here differ somewhat from the totals in 2 Samuel 24:9. These totals are as follows:
Chronicles
Israel 1,100,000
Judah 470,000
Total 1,570,000
Samuel
Israel 800,000
Judah 500,000
Total 1,300,000
It is possible that the figure in Chronicles of 1,100,000 includes the total of David’s standing army, 288,000 men (chapter 27:1-15). In round numbers this would be 300,000 men, which, added to the 800,000 of Samuel, would make 1,100,000. The 500,000 of Samuel for Judah may also be a round number for the chronicler’s more exact figure of 470,000 (see further on 2 Samuel 24:9). The number of warriors in Israel had increased considerably since the Exodus, when the total, excluding Levites, stood at 603,550 (Numbers 1:46). See Introduction to Chronicles.