2 Samuel 16:5-7, 9-10

When King David came to Bahurim, there came out a man of the family of the house of Saul, whose name was Shimei, the son of Gera, and as he came he cursed continually. And he threw stones at David and at all the servants of King David, and all the people and all the mighty men were on his right hand and on his left. And Shimei said as he cursed, “Get out, get out, you man of blood, you worthless man!

Then Abishai the son of Zeruiah said to the king, “Why should this dead dog curse my lord the king? Let me go over and take off his head.” 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?’”