And Nathan said to David, Thou art the man. 2 Samuel 12:7.
As time passed on, David's sin toward Bathsheba became known, and suspicion was excited that he had planned the death of Uriah. The Lord was dishonored. He had favored and exalted David, and David's sin misrepresented the character of God and cast reproach upon His name. It tended to lower the standard of godliness in Israel, to lessen in many minds the abhorrence of sin; while those who did not love and fear God were by it emboldened in transgression.
Nathan the prophet was bidden to bear a message of reproof to David. It was a message terrible in its severity. To few sovereigns could such a reproof be given but at the price of certain death to the reprover. Nathan delivered the divine sentence unflinchingly, yet with such heaven-born wisdom as to engage the sympathies of the king, to arouse his conscience, and to call from his lips the sentence of death upon himself....
The guilty may attempt, as David had done, to conceal their crime from men; they may seek to bury the evil deed forever from human sight or knowledge; but “all things are naked and opened unto the eyes of him with whom we have to do” (Hebrews 4:13).38Ibid., 720, 721.
The prophet Nathan's parable of the ewe lamb, given to King David, may be studied by all.... While he was following his course of self-indulgence and commandment breaking, the parable of a rich man who took from a poor man his one ewe lamb, was presented before him. But the king was so completely wrapped in his garments of sin, that he did not see that he was the sinner. He fell into the trap, and ... passed his sentence upon another man, as he supposed, condemning him to death....
This experience was most painful to David, but it was most beneficial. But for the mirror which Nathan held up before him, in which he so clearly recognized his own likeness, he would have gone on unconvicted of his heinous sin, and would have been ruined. The conviction of his guilt was the saving of his soul. He saw himself in another light, as the Lord saw him, and as long as he lived he repented of his sin.39The S.D.A. Bible Commentary 2:1023.
From Conflict and Courage - Page 179