2 Samuel 24:8-10

8Having gone through the entire land for nine months and twenty days, they returned to Jerusalem.

9Joab reported the number of people to the king. There were 800,000 capable warriors in Israel who could handle a sword, and 500,000 in Judah.

10But after he had taken the census, David’s conscience began to bother him. And he said to the Lord, “I have sinned greatly by taking this census. Please forgive my guilt, Lord, for doing this foolish thing.”