Compare the passage in Chronicles. The account here is abridged; and 2 Samuel 24:18 has the appearance of being the original statement.
Related Commentaries of 2 Samuel 24:17
2 Samuel 24:17
17 And David spake unto the LORD when he saw the angel that smote the people, and said, Lo, I have sinned, and I have done wickedly: but these sheep, what have they done? let thine hand, I pray thee, be against me, and against my father's house.