2 Samuel 24:8-10

8After they had gone through the entire land, they came back to Jerusalem at the end of nine months and twenty days.

9Joab reported the number of the fighting men to the king: In Israel there were eight hundred thousand able-bodied men who could handle a sword, and in Judah five hundred thousand.

10David was conscience-stricken after he had counted the fighting men, and he said to the Lord, “I have sinned greatly in what I have done. Now, Lord, I beg you, take away the guilt of your servant. I have done a very foolish thing.”