But the king said, “What have I to do with you, you sons of Zeruiah? If he is cursing because the LORD has said to him, ‘Curse David,’ who then shall say, ‘Why have you done so?’”
We here find how David bore Shimei's curses much better than he had borne Ziba's flatteries. By the latter he was brought to pass a wrong judgment on another, by the former to pass a right judgment on himself. The world's smiles are more dangerous than its frowns. Observe here, I.
Commenting on 2 Samuel 16:5-14
And the king said, what have I to do with you, ye sons of Zeruiah?.... It seems as if Joab, the brother of Abishai, joined with him in this request to have leave to take off the head of Shimei; and though David had to do with them as his relations, his sister's sons, and as they were generals in his army; yet in this...
And the king said, What have I to do with you, ye sons of Zeruiah? so let him curse, because the LORD hath said unto him, Curse David. Who shall then say, Wherefore hast thou done so? (f) David felt that this was the judgment of God for his sin, and therefore humbles himself to his rod.