2 Samuel 24:8-10

Amplified Bible

⁸ So when they had gone about through all the land [taking the census], they came to Jerusalem at the end of nine months and twenty days. ⁹ And Joab gave the sum of the census of the people to the king. In Israel there were 800,000 valiant men who drew the sword, and the men of Judah were 500,000.

¹⁰ But David’s heart (conscience) troubled him after he had counted the people. David said to the Lord, “I have sinned greatly in what I have done. But now, O Lord, please take away the sin of Your servant, for I have acted very foolishly.”