Charles Ellicott Commentary 2 Samuel 12:7

"And Nathan said to David, Thou art the man. Thus saith Jehovah, the God of Israel, I anointed thee king over Israel, and I delivered thee out of the hand of Saul;" — 2 Samuel 12:7 (ASV)

Thou art the man. —The boldness and suddenness of this application brought a shock to David which at once aroused his slumbering conscience. This could not have been the case had David been essentially a bad man. He was a man whose main purpose in life was to do God’s will, but he had yielded to temptation, had been entangled in further and greater guilt in the effort to conceal his sin, and all the while his conscience had been stupefied by the delirium of prosperity and power. Now what he had done is suddenly brought before him in its true light. For like prophetic rebukes of royal offenders see 1 Samuel 15:21–23; 1 Kings 21:21–24; Isaiah 7:3–25; Matthew 14:3–5.