2 Samuel 24:8-10

8And they went through all the land, and came to Jerusalem at the end of nine months and twenty days.

9And Joab gave the sum of the number of the people to the king; and there were of Israel eight hundred thousand valiant men that drew sword; and the men of Judah were five hundred thousand men.

10And David's heart smote him after he had numbered the people. And David said to Jehovah, I have sinned greatly in what I have done; and now, I beseech thee, Jehovah, put away the iniquity of thy servant; for I have done very foolishly.