2 Samuel 24:8-10 (KJV)

8 So when they had gone through all the land, they came to Jerusalem at the end of nine months and twenty days. 9 And Joab gave up the sum of the number of the people unto the king: and there were in Israel eight hundred thousand valiant men that drew the sword; and the men of Judah were five hundred thousand men. 10 And David's heart smote him after that he had numbered the people. And David said unto the LORD, I have sinned greatly in that I have done: and now, I beseech thee, O LORD, take away the iniquity of thy servant; for I have done very foolishly.